Aircraft turbine engine with means for detecting axial displacement of fan

Abstract

The invention relates to an aircraft turbine engine comprising: a fan (12) rotatable about a longitudinal axis and comprising a rotor disc (30) and variable angle pitch blades (32) mounted on the periphery of the rotor disc, and a system (50) for determining the angular pitch position of the blades, comprising:-a plurality of pitch reference members (52) rigidly attached to the disc,-a position reference element (58), -a component (62) rigidly attached to the blade and capable of changing the angular position with respect to the component in the event of a change in the angular pitch of the blade,-a sensor (62) fixed with respect to the fan and capable of determining the relative angular position between the element and the component by detecting the stroke of the element and the component during rotation of the fan. The turbine engine is configured to detect the axial displacement of the fan by detecting the axial displacement of the member from the sensor.

Description

Technical Field

[0001] The present disclosure relates to an aircraft turbine having a device for detecting an axial displacement of a fan, and a method for detecting an axial displacement of a fan of an aircraft turbine. Background Art

[0002] In an aircraft turbine with or without a ducted fan, it is known to handle a situation where a mechanical failure occurs in the mechanical components connecting the fan to the rest of the engine and causes the fan to fall off.

[0003] Engine manufacturers have come up with several solutions to avoid such events: - Integrating a system for holding the fan involving mechanical stops; - Adding sensors and then disconnecting the sensors in the manner of a mechanical fuse in the case of an axial displacement of the fan; - Mounting a double skin on the mechanical elements so as to be able to hold the fan relying on another mechanical force path. Summary of the Invention

[0004] Although these systems have proven to be satisfactory, there is still a need to simply detect the axial displacement of the fan.

[0005] Accordingly, the subject of the present invention is an aircraft turbine, comprising: a fan that can rotate about a longitudinal axis XX', and comprising a rotor disk and a plurality of blades with variable angle settings mounted on the periphery of the disk; a system for determining the angular setting position of at least one blade, comprising: - a number of setting reference members fixed to the rotor disk; - a position reference element fixed to at least one blade and capable of changing its angular position relative to the setting reference members in the case where the angular setting of at least one blade changes; - at least one sensor that is fixedly positioned relative to the fan and capable of determining the relative angular position between the position reference element and the setting reference members by detecting the passage of the position reference element and the setting reference members during the rotation of the fan, characterized in that the turbine is configured to detect the axial displacement of the fan by detecting the axial displacement of the setting reference members based on at least one sensor.

[0006] Use at least some components of the system (the set reference members (the object or the claw and (one or more) sensors)) to determine the angular setting position of the turbine blade, so that the axial displacement of several set reference members can be simply detected, and thus the axial displacement of the fan can be detected. Even if some structural modifications can be made to the existing components as the case may be, using these existing components also makes it possible to avoid adding dedicated components (especially one or more sensors), which simplifies the construction, setting and maintenance of the turbine, and does not increase the on-board weight or volume. In addition, by using one or more existing sensors, the electronics are simplified because the function is increased without increasing the number of inputs and outputs of the electronic control unit or the processing unit.

[0007] According to other possible features, individually or in combination: - The turbine includes a processing unit configured to process at least one signal generated by the at least one sensor to detect the axial displacement of the set reference member; - The processing includes comparing at least one signal generated by at least one sensor with at least one reference signal representing the non-offset axial position of the set reference member, and detecting the axial displacement of the set reference member in the case where a difference from the at least one reference signal is determined; - The processing includes analyzing at least one signal generated by at least one sensor that includes several consecutive signal portions, and detecting the axial displacement of the set reference member in the case where a signal portion having a shorter period or a smaller amplitude than other signal portions of the at least one signal being analyzed is detected in the at least one signal thus analyzed; - At least one set reference member has an elongated integral shape along the longitudinal axis and extends from a first end to an opposite second end, the second end being closer to the at least one sensor than the first end, and the width being reduced compared to the first end; - At least one set reference member has an elongated integral shape along the longitudinal axis and extends from a first end to an opposite second end, the second end being closer to the at least one sensor than the first end, and the thickness being reduced compared to the first end; - The set reference members are distributed along the perimeter of the rotor disk; - The set reference members are distributed as groups of set reference members or several groups of set reference members distributed along the perimeter of the rotor disk; - At least some of these groups of set reference members each include at least two or three consecutive set reference members; - The turbine is configured to confirm the detection of the axial displacement by detecting the axial displacement at least twice based on the same group of set reference members, or by detecting the axial displacement at least twice based on at least two different groups of set reference members; - The turbine includes a system for controlling the operation of the turbine, which is configured to stop the operation of the turbine in the event of detecting an axial displacement of the fan; - The at least one sensor is selected from a variable reluctance sensor, a capacitance sensor, an inductance sensor, and an optical sensor; - The at least one sensor includes a plurality of sensors; - The turbine is further configured to determine the rotational speed of the fan based on the at least one sensor; - The turbine includes a reduction gearbox to which the fan is connected; - The turbine includes an axial mechanical stop that is used to axially retain the fan in the event of an axial displacement of the fan.

[0008] The present invention also relates to a method for detecting an axial displacement of a turbine fan that is rotatable about a longitudinal axis XX' and includes a rotor disk and a plurality of blades with variable angle settings mounted on the periphery of the disk. The detection method includes, on the one hand, using a plurality of set reference members fixed to the rotor disk and at least one sensor that is fixedly positioned relative to the trajectories of the fan and the set reference members during rotation of the fan to detect the axial displacement of the fan based on the detection of the axial displacement of the set reference members. The set reference members and the at least one detector are used to determine the angular setting positions of at least one blade.

[0009] This method provides the same advantages as those turbines briefly described above and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Other features and advantages of the subject matter of the present invention will be revealed from the following description of the embodiments, which are given by way of non-limiting examples with reference to the accompanying drawings.

[0011] Figure 1 Figure 1 is a schematic overall axial cross-sectional view of an aircraft turbine according to an embodiment of the present invention;

[0012] Figure 2 Figure 2 is Figure 1 an enlarged schematic overall axial half-sectional view of a part of the turbine shown in a possible configuration;

[0013] Figure 3 Figure 3 is a schematic overall perspective view showing the layout of different components relative to the fan blades;

[0014] Figure 4 Figure 4 is Figure 3 a schematic partial top view of a part of the component shown;​​​​​​​​

[0015] Figure 5 Figure 5 is Figure 4 a schematic partial perspective view of the component shown;

[0016] Figure 6 Figure 6 is a schematic diagram showing an example of a series of signals detected by a sensor as shown Figures 3 to 5 ;

[0017] Figure 7 Figure 7 is a schematic diagram showing the signal detected by the sensor at the input section of a threshold comparator;

[0018] Figure 8 Figure 8 is a schematic diagram showing the Figure 7 signal at the output section of the comparator;

[0019] Figure 9 Figure 9 is a schematic diagram showing different functional components of an information processing thread of a sensor;

[0020] Figure 10 Figure 10 is a schematic perspective view of a group formed by three angle setting reference members according to an exemplary embodiment;

[0021] Figure 11 Figure 11 is a schematic diagram similar to Figure 4 after axial displacement of a fan;

[0022] Figure 12 Figure 12 is a schematic diagram showing both the signal detected by the sensor at the input section of a threshold comparator and the signal at the output section of this comparator, wherein there is a difference between the periods of consecutive signal portions;

[0023] Figure 13A Figure 13A is a side view schematic diagram of an angle setting reference member according to another exemplary embodiment;

[0024] Figure 13B Figure 13B is a schematic perspective view of a group formed by three angle setting reference members according to an exemplary embodiment;

[0025] Figure 14 Figure 14 is a schematic diagram of the signal detected by the sensor, showing an amplitude difference between consecutive signal portions. DETAILED DESCRIPTION ​​​​​​​​​​​​​​​​​​​​​​

[0026] Figure 1 The aircraft turbine 10 according to an embodiment of the present invention is schematically shown along a longitudinal section, such as a bypass turbofan engine. Other types of turbines may alternatively be contemplated.

[0027] The turbine 10 herein includes, in the circulation of the air flow from upstream to downstream, a ducted fan 12, a low-pressure compressor 14, a high-pressure compressor 16, a combustion chamber 18, a high-pressure turbine 20, and a low-pressure turbine 22. All these elements act in a known manner on a first annular air flow circulating in a first central duct 24 coaxial with the axis XX'. A second bypass annular duct 26 concentrically surrounds the first central duct for the flow of a second annular air flow. Other turbofan engine configurations may alternatively be contemplated as having a single compressor and a single turbine, or having more than two compressors and more than two turbines, or even having a ducted propeller.

[0028] The fan 12, which is capable of rotating about the longitudinal axis XX', includes a rotor disk 30 and a plurality of blades 32 with variable angle setting members. Each blade is mounted on the outer periphery of the disk along the perimeter of the disk in a known manner. Each blade 32 extends away from the outer periphery of the disk 30 along a radial direction relative to the longitudinal axis XX'. Each blade 32 also extends along an axial direction and has a suitable aerodynamic profile.

[0029] The rotor disk 30 is directly connected here to the low-pressure shaft of the turbine or is connected to the low-pressure shaft of the turbine by means of a reduction gearbox. The disk forms part of the central structure of the engine of the turbine 10.

[0030] Figure 2 Also shown schematically Figure 1 in an enlarged partial form (along an axial half-section) of the turbine are the main elements that may be involved in the mechanical assembly of the reduction gearbox connecting the fan 12 to the turbofan engine in an exemplary embodiment (note that this is only one possible setting configuration of the fan, and of course other configurations may be contemplated). Thus, the disk 30 of the fan 12 can be mounted on a shaft 34 extending downstream in the form of an engagement portion 36, which mechanically engages with the reduction gearbox 38. In this exemplary embodiment, the reduction gearbox 38 may include a planet carrier 38a and a sun gear 38c. A planetary section is provided within the planet carrier 38a, and one of the planetary sections 38b is shown therein. At the same time, the sun gear 38c is connected to the shaft of the downstream low-pressure compressor 14 (not shown here).

[0031] The support portion 40 is concentrically mounted on the outer surface of the shaft 34 (on the portion where the diameter of the shaft is widened), between the upstream portion of the shaft connected to the disk 30 and the downstream engagement portion 36. The shroud 42 is mounted on the support portion 40 via its inner periphery 42a and on the axial stop 44 via its outer periphery 42b, only a part of the axial stop being shown here. The axial stop 44 serves as a stop in the event of an undesired axial displacement of the fan. In Figure 2 , the regions Z1 and Z2 represent vulnerable regions where the mechanical couplings are liable to fail in the event of an undesired axial displacement of the fan. This is also the case at the bearing of the axial stop 44 and at the connection between the shaft 34 and the downstream engagement portion 36 (region Z2), since the housing 38 is not designed to withstand axial forces. Failures can also occur downstream, i.e., inside the housing 38.

[0032] A known mechanism for changing the angular position of the blades (not shown) is incorporated into the turbine so as to orient each blade about the radial extension direction of each blade according to the angular setting requirements of the fan operation. This mechanism generally acts on the support portion at the root of the blade and properly orients the blade root from inside the rotor disk.

[0033] Figure 3 is a schematic partial perspective view of the fan 12, which is equipped with blades 32, only part of which is shown, and a part 48 is rotatably fixed to the rotor disk 30 of the fan in front of the blades 32. Here, the part 48 is in the form of a shroud or a disk, and the outer peripheral edge is folded to form an edge substantially having the shape of a circular cylinder rotating about the longitudinal axis XX'. However, the part 48 can take other alternative forms not shown here. A system 50 for determining the angular setting position of the blades is mounted relative to the fan 12 and includes several components incorporated into the turbine, at least some of which are used to detect the axial displacement (change in axial position) of the fan.

[0034] The system 50 generally includes a number of setting reference members (targets or claws) 52, which are fixed to the rotor disk 30 by means of the shroud 48 and thus rotate with the latter during the rotation of the fan. In the present example, the setting reference members 52 are grouped, for example, in the form of several groups or clusters (at least two groups or clusters) of several members 52 each distributed along the circumference of the shroud. For example, there are two groups G1, G2, each group having two members 52, which are arranged on the shroud in a radially opposite manner; and there is also a group G3, each group having three members 52, which are arranged at an angle of 90° relative to each of the two groups G1, G2. Although the system here includes more than two members 52, it should be noted that, from a functional point of view, only two members 52 are sufficient to determine the axial displacement of the fan.

[0035] In this example, in each group, the reference members 52 are set to be laterally separated from each other along a direction corresponding to the circumferential direction of the shroud, and they meet at a shared base, thereby forming a kind of rake or fork. Other ways of forming the grouped members 52 can be used alternatively.

[0036] Figure 4 A top view showing the layout of group G3 (without the shroud 48) and the layout of a number of sockets 54 located on the outer periphery of the rotor disk 30 for mounting blades (the blades are not shown here). In each socket 54, a blade support 56 can be seen, which is used to receive the root of the corresponding blade. In this example, each member 52 has an elongated integral shape along the longitudinal axis and tapers from a first end 52a located at the base of the group to a relative second free end 52b away from the base.

[0037] The system 50 generally further includes a position reference element 58, which is called a needle and is fixed to the blade, and is positioned as it is when the blade is present. The needle 58 has an elongated integral shape, which extends away from the blade from a widened base fixed to, for example, the blade support (alternatively, the needle can be attached to the blade). As Figure 4 shown, the needle 58 is not aligned along the axis XX', but forms an angular spacing therewith, which indicates that the angular orientation (setting) of the blade is liable to change during the operation of the fan. Therefore, in the case of a controlled modification of the blade angle setting by the above mechanism, the needle 58 can change its angular position relative to the setting reference member 52. Thus, as Figure 3 shown, the angular orientation of the needle can change over time and can be closer to or farther from the setting reference member 52. Note that from a functional point of view, as described herein, a needle is not required to determine the axial displacement of the fan.

[0038] Returning to Figure 3 , a number of through openings 60 are formed in the thickness of the shroud and are circumferentially distributed on the shroud to allow the needle 58 mounted on the blade to extend through these openings. The angular span of each opening 60 is sized such that it can cover the entire angular deviation range of the needle in question. As Figure 3 shown, only certain blades 32 are equipped with needles. In the example considered, only four blades are involved, so the shroud 48 includes four openings 60.

[0039] The system 50 generally further includes at least one sensor 62, which is fixedly positioned relative to the fan. The at least one sensor 62 described here is attached to a stator forming part of the turbine. In the example shown, a number of, for example, four sensors 62 are used.

[0040] In Figure 3 , the sensor 62 is mounted on the sensor support 64, inFigure 4 In this case, the sensor support 64 is mechanically fixed to the partially shown stator portion 66. Alternatively, other mounting means for one or more sensors can be envisaged.

[0041] Figure 5 is Figure 4 A partial rear stereoscopic view of the magnifying glass of the device, showing the relative arrangement of the sensor 62, the needle 58, and the setting reference member 52.

[0042] Generally, one or more sensors 62 can determine the relative angular position between the needle 58 and the setting reference member 52 by detecting the passage of the needle and the setting reference member during the rotation of the fan. Using two setting reference members 52 makes it possible to distinguish this member and the needle relative to the sensor 62. Each sensor 62 provides a signal that is appropriately processed and known to the electronic processing unit.

[0043] Figure 6 Schematically represents a series of signals generated when different sets of the setting reference member 52 and the needle 58 are detected by the sensor. Thus, for the group G3 composed of three members 52, the signal belongs to a sine wave with three cycles, while for the groups G1 and G2 composed of two members 52, the signal is similar to a pseudo-sine wave with two cycles, and for the needle, the signal is similar to a pseudo-sine wave with a single cycle.

[0044] The electronic processing unit can pre-perform shaping operations (filtering, comparison with a threshold,...).

[0045] Figure 7 Shows a sine wave signal with three cycles injected at the input of the threshold comparator, while Figure 8 Shows the signal at the output of the comparator.

[0046] Therefore, the angular setting position of the blade can be determined, and the rotational speed of the fan can also be determined (at the rising edge of the digital signal: measuring the frequency, sampling, and conversion law of the signal generated by the sensor,...).

[0047] For example, the sensor 62 is selected from variable reluctance sensors, capacitive sensors, optical sensors,... In the embodiment described herein, the sensor or each sensor is, for example, a variable reluctance sensor.

[0048] If the fan is axially displaced towards the front of the turbine (along the Figure 4 arrow D), the signal generated by the sensor 62 (if there is only one) or each sensor 62 is modified with respect to the signal generated when the fan has no axial position change. Such a signal can be described as a reference signal representing the non-offset axial position.

[0049] According to the first embodiment, the axial offset of the fan causes the set reference members 52 to be axially recessed by a certain distance so that they no longer pass under the sensors during the rotation of the fan, and thus the sensor or sensors no longer detect the passage of these members. Therefore, this situation results in a signal loss (loss of angular setting information). For this reason, the members 52 have a calibrated length, that is, the length is dimensioned to detect an axially displacement of a predetermined amplitude.

[0050] As Figure 9 shown, the turbine 10, in addition to the electronic processing unit UT, also includes a control system SC for the operation of the turbine, and the control system SC is configured to stop the operation of the turbine in the case of detecting an axial displacement of the fan, for example, by cutting off the fuel supply.

[0051] In this example, when the signal is thus lost by one or more sensors 62, the information related to the loss of information from the sensor or sensors 62 is transmitted by the electronic processing unit UT to the control system SC, which controls the operation of the turbine and stops supplying fuel to the engine. For example, the system SC sends a command to the fuel supply system SA, or more specifically, to the supply valve to close it.

[0052] Note that before deciding to stop the operation of the turbine, it is preferable to confirm the detection result of the axial displacement of the fan. This can be achieved by performing multiple detections that will all produce the same result. For example, such confirmation can be carried out by continuously detecting the signal loss at least twice during the passage of the same members 52 in the same group, or by detecting the signal loss during the passage of several members that belong to different groups and are not necessarily consecutive. In practice, the detection of the signal loss (the action that causes the engine to shut down) is manifested as noticing that there is no signal within a given time period.

[0053] According to the second embodiment, the amplitude of the axial offset of the fan can be smaller than that of the first mode, for example, in the case where the axial stop is close to the fan. In this case, although in the recess, the set reference members 52 can still be detected by one or more sensors during the rotation of the fan.

[0054] As Figure 10 shown, at least one member 52 can have a free end 52b (the end positioned close to one or more sensors), which is tapered or thinned compared to the opposite end 52a connected to the base of the group G3 in this example. This thinning is carried out along the length l of one or more members 52 and applies to all members of the group in this drawing. Note that this description also applies to a group consisting of two members 52.

[0055] Figure 11 The fan is shown relative to Figure 4The offset axial position of the position. The horizontal reference line L represents the axial position that one or more sensors 62 can detect. It can be seen that in Figure 11 of [0000197], the tapered end 52b of the member 52 is superimposed on this line.

[0056] As described above, the signal generated by the sensor 62, or when there are several sensors, the signal generated by each sensor 62 includes a series of two signal parts, and these two signal parts can be similar to a sine wave or a pseudo-sine wave.

[0057] In the second embodiment, the axial displacement of the fan can be detected based on a group of three members 52, wherein only the free end 52b of the middle member 52 is tapered (different from Figure 10 ). This arrangement enables the detection of the difference between the signal part corresponding to the middle member 52 of the group and the two signal parts around the two end members 52 in the signal from one or more sensors. The free ends of the two end members are not tapered. Note that several sets of set reference members can be used for detection.

[0058] Figure 12 Shows the appearance of the signal generated by the sensor, and the sensor can see the passage of the group of members 52, wherein only the end of the middle member is tapered, and the two end members maintain the nominal width at their free ends. This figure shows the signal S1 at the input part of the comparator and the slot-shaped signal S2 at the output part of the comparator. The signal processing performed by the processing unit UT on Figure 12 the signal S2 enables the shortest period P2 to be identified from the consecutive periods P1, P2, and P3 of the three consecutive signal parts, which is due to the smaller width of the free end of the middle member 52. Detecting the period P2 in the signal from the sensor, or if there are several sensors, detecting the period P2 in the signal from each sensor enables the axial displacement of the fan to be detected.

[0059] For the first embodiment, before stopping the operation of the turbine, this axial displacement information is confirmed by performing similar detections on other groups of members 52. Alternatively, this information can be confirmed by several consecutive detections (for example, two or three times) or by completing one full rotation of the disk.

[0060] If the detection of the axial displacement of the fan is completed based on one or more signals generated by detecting the passage of a group of two members 52, a single member of the two members can have a tapered end. Therefore, the analysis of the resulting signal will enable the determination of two different consecutive periods of the group, which will enable the conclusion that the fan has an axial displacement to be drawn.

[0061] Alternatively, as previously described, axial displacement detection can be accomplished with all of the set reference members 52 of the same set (or several sets of two, three, or more members 52 per set) having a tapered free end. During processing of the signal generated by detecting the passage of such a set, unit UT continues to compare the signal with a reference signal stored in the unit's memory or a memory associated with the unit. The reference signal was previously obtained based on members (or several sets of members) having the same nominal width from one end to the other.

[0062] Note that in order to measure the speed of the fan, the signal is processed as Figure 12 shown, triggering a flip-flop when the signal exceeds a certain positive threshold, and when the signal 10 goes to zero volts, using the triggered flip-flop to obtain a reference time and calculating the signal period as the duration between two acquisitions of the reference time.

[0063] A third embodiment will now be described. According to this mode, at least one set reference member 52' is structurally modified such that the signal generated when the member passes in front of one or more sensors represents such a modification.

[0064] As Figure 13A shown, member 52' has a free end 52b' (as close as possible to one or more sensors) whose thickness is reduced compared to the nominal thickness e of the member. Figure 13B A group G3' is shown, which consists of three members 52', all of which have a free end 52b' with a reduced thickness. Note that the lateral or side spacing between two consecutive members or claws 52' is determined according to an angular setting range, in particular to avoid confusing the detection of a group of three members with the detection of a group of two members followed by a needle. This note also applies to the other embodiments described previously.

[0065] In this third embodiment, the axial displacement of the fan can be detected based on a group of three members 52', where only the free end 52b' of the middle member 52' has a reduced thickness (as opposed to Figure 13B different). This arrangement enables the detection of the difference between the signal portion corresponding to the middle member 52' of the group and the two signal portions corresponding to the two end members 52' (each end member having a free end with a constant nominal thickness) around the middle member 52' in the signal from one or more sensors.

[0066] Figure 14 Shows the appearance of the signal generated by a sensor that sees the passage of a group of members 52', where only the end thickness of the middle member is reduced and the free ends of the two end members remain at the nominal thickness e. This figure shows the output signal of the sensor. The processing unit UT pairs Figure 14The signal processing performed on the signal enables the identification of the portion with the smallest amplitude from among three consecutive signal portions that make up the signal (in this case, the second signal portion surrounded by two signal portions of two end members 52' corresponding to the nominal thickness). This is because the thickness of the free end of the intermediate member 52' is reduced, increasing the air gap between the member 52' and the sensor or each sensor. The smaller amplitude A2 is detected by comparing it with two amplitudes A1 and A3 in the signal from the sensor, or if there are several sensors, the amplitudes of each sensor are detected, enabling the detection of the axial displacement of the fan.

[0067] For the first two embodiments, this information is confirmed, for example, by performing a similar detection on other sets of members 52' before stopping the turbine operation. Alternatively, this information can be confirmed by several consecutive detections (e.g., two or three times) or by completing one full rotation of the disk.

[0068] Regarding the second embodiment, in the case of detecting the axial displacement of the fan based on one or more signals generated by detecting the passage of a group of two members 52', a single member of the two members can have a tapered end. Thus, the analysis of the resulting signal will enable the determination of two different consecutive amplitudes of the group, which will enable the conclusion that the fan has undergone an axial displacement.

[0069] Alternatively, as previously mentioned, the detection of axial displacement can be accomplished using all the set reference members 52' of the same group (or several groups of two, three, or more members 52' each) having a reduced thickness at the free end. During the processing of the signal generated by detecting the passage of such a group, the unit UT continues to compare the signal with a reference signal stored in the memory of the unit or in a memory associated with the unit. The reference signal was previously obtained based on a group of members having the same nominal thickness from one end to the other.

[0070] The electronic processing unit or electronic control unit UT of the turbine is configured to implement a method for detecting the axial displacement of the fan according to one or more embodiments of the present invention. Such a method particularly includes the following steps: detecting a signal through one or more sensors during the passage of a plurality of angularly set reference members (optionally combined into one or more groups), and then processing the signal, optionally by comparing the signal with at least one reference signal representing the non-offset axial position of the fan to detect the axial displacement of the plurality of angularly set reference members.

[0071] The present invention is equally applicable to turbines equipped with a reduction gearbox and turbines without a reduction gearbox.

[0072] Although this specification describes specific exemplary embodiments, modifications may be applied to these embodiments without departing from the overall scope of the invention as defined by the claims. Additionally, the various features of different embodiments illustrated or mentioned may be combined into additional embodiments. Accordingly, the specification and drawings must be considered in an illustrative rather than a restrictive sense.

Claims

1. An aircraft turbine, comprising: a fan (12) capable of rotating about a longitudinal axis (XX'), and comprising a rotor disc (30) and a plurality of blades (32) with variable angle settings mounted on the periphery of the disc; a system (50) for determining the angle setting position of at least one blade, comprising: - a number of setting reference members (52; 52') fixed to the rotor disc; - a position reference element (58) fixed to the at least one blade (32) and capable of changing its angular position relative to the setting reference members (52; 52') when the angle setting of the at least one blade changes; - at least one sensor (62) positioned fixedly relative to the fan (12) and capable of determining the relative angular position between the position reference element (58) and the setting reference members (52; 52') by detecting the passage of the position reference element and the setting reference members during rotation of the fan; characterized in that the turbine is configured to detect the axial displacement of the fan by detecting the axial displacement of the setting reference members (52; 52') based on the detection by the at least one sensor (62).

2. The turbine according to claim 1, characterized in that, The turbine comprises a processing unit (UT) configured to process at least one signal generated by the at least one sensor to detect the axial displacement of the setting reference members (52; 52').

3. The turbine according to claim 2, characterized in that, The processing comprises: comparing the at least one signal generated by the at least one sensor (62) with at least one reference signal representing the non-offset axial position of the setting reference members (52; 52'), and detecting the axial displacement of the setting reference members (52) when a difference from the at least one reference signal is determined.

4. The turbine according to claim 2, characterized in that, The processing: comprises analyzing the at least one signal generated by the at least one sensor (62) which comprises a number of successive signal portions, and detecting the axial displacement of the setting reference members (52; 52') when a signal portion is detected in the at least one signal thus analyzed which has a shorter period or a smaller amplitude than other signal portions of the at least one signal being analyzed.

5. The turbine according to any one of claims 1 to 4, characterized in that, At least one setting reference member (52; 52') has an overall shape elongated along the longitudinal axis and extends from a first end (52a) to an opposite second end (52b), the second end being closer to the at least one sensor (62) than the first end and having a reduced width compared to the first end.

6. The turbine according to any one of claims 1 to 4, characterized in that, At least one setting reference member (52; 52') has an overall shape elongated along the longitudinal axis and extends from a first end (52a') to an opposite second end (52b'), the second end being closer to the at least one sensor (62) than the first end and having a reduced thickness compared to the first end.

7. The turbine according to any one of claims 1 to 6, characterized in that, The setting reference members (52; 52') are distributed along the perimeter of the rotor disc.

8. The turbine according to the preceding claim, characterized in that, The set reference members (52; 52') are distributed in groups of set reference members (52; 52') or in several groups of set reference members (52; 52') distributed along the perimeter of the rotor disk.

9. The turbine according to the preceding claim, characterized in that, At least some of the groups of the set reference members each include at least two or three consecutive set reference members (52; 52').

10. The turbine according to claim 8 or 9, characterized in that, The turbine is configured to confirm the detection of the axial displacement by detecting the axial displacement at least twice based on the same group of set reference members (52; 52') or by detecting the axial displacement at least twice based on at least two different groups of set reference members (52; 52').

11. The turbine according to any one of claims 1 to 10, characterized in that, The turbine includes a system for controlling the operation of the turbine, and the system is configured to stop the operation of the turbine when the axial displacement of the fan is detected.

12. The turbine according to any one of claims 1 to 11, characterized in that, The at least one sensor (62) is selected from a variable reluctance sensor, a capacitance sensor, an inductance sensor, and an optical sensor.

13. The turbine according to any one of claims 1 to 12, characterized in that, The turbine is further configured to determine the rotational speed of the fan (12) based on the at least one sensor (62).

14. The turbine according to any one of claims 1 to 13, characterized in that, The turbine includes a reduction gearbox (38), and the fan is connected to the reduction gearbox.

15. A detection method for detecting the axial displacement of a fan (12) of a turbine, the fan being rotatable about a longitudinal axis (XX') and including a rotor disk (30) and a plurality of blades (32) with variable angle settings mounted on the periphery of the disk; The detection method on the one hand includes using a plurality of set reference members (52; 52') fixed to the rotor disk and at least one sensor (62) fixedly positioned on the trajectory of the set reference members relative to the fan during the rotation of the fan to detect the axial displacement of the fan (12) based on the detection of the axial displacement of the set reference members (52; 52'), and the set reference members (52; 52') and the at least one sensor (62) are used to determine the angular setting position of at least one blade (32).

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