IMPROVED RELIABILITY THRUSH REVERSER

Abstract

Thrust reverser (100) comprising: a fixed structure (20) and a movable structure (21) mounted opposite an opening (22); an actuator (30-33) for selectively moving the movable structure (21) between a direct jet position and a thrust reversal position; wherein the thrust reverser (100) comprises a measuring device (91) for the distance between a first measuring point and a second measuring point which is integral with the movable structure (21), and one of the measuring points comprises a emitter (80) of a wave stream (82) and the other of the measuring points comprises a reflector element (83) for at least a portion of the wave stream (82). Figure for the abstract: Fig. 1

Description

Title of the invention: THRUST REVERSER WITH IMPROVED RELIABILITY Technical field of the invention

[0001] The present invention relates to a thrust reversal system for a turbojet engine nacelle. The invention also relates to a turbojet engine nacelle incorporating a thrust reversal system according to the invention. State of the prior art

[0002] An aircraft is powered by several turbojet engines, each housed in a nacelle also housing a set of ancillary actuation devices linked to its operation and providing various functions when the turbojet engine is in operation or stopped. These ancillary actuation devices include in particular a thrust reverser system also called a thrust reverser.

[0003] A nacelle generally has a tubular structure comprising an air inlet upstream of the turbojet engine, a middle section intended to surround a fan of the turbojet engine, a downstream section integrating thrust reversal means and intended to surround the combustion chamber of the turbojet engine, and is generally terminated by an ejection nozzle whose outlet is located downstream of the turbojet engine.

[0004] Modern nacelles are designed to house a dual-flow turbojet engine capable of generating, via the rotating fan blades, a hot air flow (primary flow) and a cold air flow (secondary flow) which circulates outside the turbojet engine through an annular passage, also called a vein, formed between a fairing of the turbojet engine and an internal wall of the nacelle. The two air flows are ejected from the turbojet engine through the rear of the nacelle.

[0005] The role of a thrust reverser is, when an aircraft is landing, to improve its braking capacity by redirecting at least part of the air ejected from the turbojet engine forward. In this phase, the reverser obstructs at least part of the cold flow stream and directs this flow towards the front of the nacelle, thereby generating counter-thrust which adds to the braking of the aircraft's wheels.

[0006] A thrust reversal system conventionally comprises a cowl slidably mounted opposite an opening made in a partition at least partially delimiting a flow of a turbojet. The opening is intended for the passage of the diverted flow and is, in direct jet operation of the nacelle, closed by the external cowl. In reverse jet operation, the cowl releases the opening by means of linear actuators for moving the cowl, of the cylinder type. A flow diversion flap can also be activated. The cylinders extend upstream of the opening generally between a fixed portion of the nacelle and a hood frame.

[0007] The aircraft computers require information on the position and / or opening status of the cowl. This information is generally provided by an encoder placed on the cylinder. This is frequently a rotary encoder which measures the number of rotations of a screw linked to the output of the rod in the case of cylinders with an electric gear motor. Hydraulic cylinders generally incorporate a linear displacement sensor of the LVDT type which measures a deployed length of the rod.

[0008] Taking measurements directly on the actuator makes it possible to have sensors protected from external conditions. However, in order to have precise position information (of the order of a millimeter on the position of the movable cover), it is necessary to have sensors and an associated kinematic chain of great precision, in particular with reduced clearances. Such arrangements impose very high manufacturing costs for the device and instrumentation costs. The installation of the cylinders and their sensors also requires costly adjustment and calibration operations.

[0009] The times and costs of installation and replacement / repair of sensors and cylinders are increased due to the same adjustment and calibration operations.

[0010] In the event of a break or defect in the kinematic chain connecting the cylinder to the hood, erroneous inverter status information may be generated without this being detectable.

[0011] Finally, the sensors currently used have significant cost and mass impacts, particularly due to the measurement technologies used (LVDT) and the provisions necessary to ensure the electromagnetic compatibility of the sensors with the aircraft environment. Subject of the invention

[0012] The present invention aims to improve the reliability of a measurement of the position of a cowl of a thrust reversal system. Presentation of the invention

[0013] For this purpose, a thrust reverser is provided which can adopt a so-called direct jet configuration and a so-called thrust reversal configuration. The thrust reverser comprises a fixed structure and a movable structure mounted opposite an opening delimited between the fixed structure and an upstream end of a movable cowl of the movable structure when the thrust reverser is in the thrust reversal configuration and an actuator for selectively moving the movable structure between the direct jet position in which the opening is closed and the thrust reversal position in which the opening is uncovered. According to the invention, the thrust reverser comprises a device for measuring a distance between a first measuring point and a second measuring point which is integral with the movable cowl. One of the measuring points comprises an emitter of a wave flux and the other of the measuring points comprises a reflecting element of at least a portion of the wave flux.

[0014] This provides a thrust reversal system in which the position and state of the movable cowl are measured directly on the sliding cowl, which makes it possible to obtain reliable and direct state information that is not dependent on the accuracy or state of the kinematic chain connecting the actuator to the sliding cowl. The installation, maintenance and replacement of such a sensor is rapid and does not require recalibration of the actuating kinematic chain.

[0015] According to other particular, non-exclusive and optional embodiments of the invention:

[0016] the measuring device is of the telemetric type by measuring the time of flight.

[0017] the system comprises a seal which, when the mobile structure is in the position for closing the opening, defines at least partially with the mobile structure a closed enclosure which extends around the first measurement point and the second measurement point;

[0018] the system comprises a sliding guide device for the movable hood which comprises at least one guide rail;

[0019] the system comprises a grid integral in translation with the mobile structure and which extends in a grid housing when the mobile structure is in its closed position, the first measurement point being located in the grid housing;

[0020] the guide device comprises a slide secured to a set of grids linked to the mobile structure and which cooperates with the guide rail and the second measuring point is located on the slide;

[0021] the measuring device is arranged so that the wave flux extends in a volume partially delimited by a core and a wing of the guide rail;

[0022] the first measuring point and the second measuring point are arranged to be contained in a protection volume defined at least partially by the mobile structure, when the mobile structure is in its closed position, but also when the mobile structure is in its released position, as well as during transit of the mobile structure between these two positions.

[0023] The invention also applies to a nacelle comprising a thrust reverser as described above.

[0024] Other characteristics and advantages of the invention will appear on reading the following description of particular non-limiting embodiments of the invention. Brief description of the figures

[0025] The invention will be better understood on reading the following description, given by way of non-limiting example, and made with reference to the figures which represent:

[0026] [Fig.l] [Fig.l] is a schematic half-sectional view of a turbojet engine equipped with a thrust reverser according to a first embodiment of the invention in a so-called “direct jet” configuration;

[0027] [Fig.2] [Fig.2] is a partial schematic half-view in section of a detail of the thrust reverser of the turbojet engine of [Fig.l];

[0028] [Fig.3] [Fig.3] is a partial schematic half-sectional view of the inverter of thrust according to a first embodiment of the invention in a thrust reversal configuration called “transverse jet”;

[0029] [Fig.4] [Fig.4] is a schematic front view of a turbojet according to the invention;

[0030] [Fig.5] [Fig.5] is a schematic view from below of a turbojet engine equipped with the thrust reverser of [Fig.l];

[0031] [Fig.6] [Fig.6] is a detailed perspective view of a thrust reverser of the turbojet engine of [Fig.4];

[0032] [Fig.7] [Fig.7] is a partial perspective view of detail similar to [Fig.6];

[0033] [Fig.8] [Fig.8] is a detail view of a distance measuring device of the thrust reverser of [Fig.l];

[0034] [Fig.9] [Fig.9] is a schematic half-sectional view of a turbojet engine equipped of a thrust reverser according to a second embodiment of the invention in a so-called “direct jet” configuration;

[0035] [Fig. 10] [Fig. 10] is a partial schematic top view of the turbojet engine of [Fig.9];

[0036] [Fig. 11] [Fig. 11] is a schematic half-sectional view of the turbojet of [Fig.9] in a thrust reversal configuration called "transverse jet";

[0037] [Fig. 12] [Fig. 12] is a partial schematic top view of the turbojet engine of [Fig.11];

[0038] [Fig. 13] [Fig. 13] is a schematic half-sectional view of a turbojet engine equipped with a thrust reverser according to a third embodiment of the invention in a so-called “direct jet” configuration;

[0039] [Fig. 14] [Fig. 14] is a partial schematic top view of the turbojet engine of [Fig.13];

[0040] [Fig. 15] [Fig. 15] is a schematic half-sectional view of the turbojet of [Fig.13] in a thrust reversal configuration called “transverse jet”;

[0041] [Fig. 16] [Fig. 16] is a partial schematic top view of the turbojet engine of [Fig.15].

[0042] In these figures, identical numerical references from one figure to another designate identical or similar elements. Furthermore, for reasons of clarity, the drawings are not to scale, unless otherwise indicated. Description of the embodiments

[0043] With reference to Figures 1 to 8, a nacelle 1 comprises a structure 2 which extends around a turbojet engine 3 whose rotating elements are mounted to rotate around a longitudinal axis Ax. Air is sucked in at the upstream part 3.1 of the turbojet engine 3 and exits through the downstream part 3.2 of the turbojet engine 3.

[0044] In the present text, the terms “upstream” and “downstream” are used with reference to the position or orientation of an element according to the direction of air flow in the turbojet and the terms “interior” or “internal” and “exterior” or “external” are used with reference to the position or orientation relative to the longitudinal axis Ax.

[0045] The structure 2 comprises an external fairing 10 which comprises an internal housing 11, here delimited by an internal wall 12 and an external wall 13. The internal wall 12 defines an external partition 14 which delimits a vein 15 for circulation of a flow 16 of the turbojet 3.

[0046] The nacelle 1 comprises a thrust reverser 100 which comprises a fixed cylindrical upstream cowl 20 and a movable downstream cowl 21 slidably mounted in a direction parallel to the axis Ax opposite a radial annular opening 22 made in the partition 14. The thrust reverser 100 also comprises four hydraulic cylinders 30, 31, 32 and 33 for selectively moving the cowl 21 between a position for closing the opening 22 ([Fig.l]) and a position for releasing the opening 22 ([Fig.2]). The cylinders 30 to 33 extend parallel to the longitudinal axis Ax and are distributed around the periphery of the nacelle 1 at ninety degrees from each other. A diverting door 25 known in itself is articulated by an arm 26 and can adopt a position of diverting the flow 16 when the opening 22 is uncovered ([Fig.3]).

[0047] MOBILE GRILLS

[0048] The thrust reverser 100 is here of the “moving grid” type and comprises two sets of grids 40 and 41 in the form of a half-cylinder and which are integral in translation with the cover 21. Each set of grids 40 and 41 extends into the housing 11 when the cover 21 is in its position for closing the opening 22 (figures 1 and 3).

[0049] The grid assembly 40 comprises a top left slider 50 which cooperates with a top left groove 60 in the form of a dovetail of a top left guide rail 61 secured to the fixed upstream cover 20. The grid assembly 40 also comprises a bottom left slider 51 which cooperates with a bottom left groove 62, also in the form of a dovetail, of a bottom left guide rail 63.

[0050] As visible in [Fig.4], the rail 61 has a projecting core 61.1 from which come an upper wing 61.2 and a lower wing 61.3 to define the upper left groove 60.

[0051] The grid assembly 41 is similar to the grid assembly 40. Thus, the grid assembly 41 comprises a top right slider 52 which cooperates with a top right groove 64 in the form of a dovetail of a top right guide rail 65 and a bottom right slider 53 which cooperates with a bottom left central groove 66, also in the form of a dovetail, of a bottom left central guide rail 67.

[0052] The rails 61, 63, 65 and 67 form, with the slides 50 to 53, a device for guiding the cover 21.

[0053] As visible in figures 4 and 5, the sets of grids 40 and 41 extend respectively opposite two sectors substantially less than one hundred and eighty degrees of the opening 22 when the cover 21 is in the position of release of the opening 22. Thus, the set of grids 40 extends opposite a left sector 22.1 of the opening 22, and the set of grids 41 extends opposite a right sector 22.2 of the opening 22.

[0054] The grids being all identical, only characteristics relating to the set of grids 40 will now be described, these being also reproduced on the set of grids 4L.

[0055] As visible in [Fig.7], the thrust reverser 100 comprises a transceiver 80 provided with a diode 81 arranged to emit a laser flux 82 to a reflective target 83 positioned on an upstream end 50.1 of the slider 50. The end 50.1 extends, here, in a transverse plane P orthogonal to the axis Ax. As visible in figures 2, 3 and 7, the transceiver 80 is connected to a support 84 secured to an extension 85 of the rail 61. The laser flux 82 extends in the rail 61 during the movement of the cover 21 towards its position of release from the opening 22, more particularly between the wings 61.2 and 61.3. The transceiver 80 comprises a seal 86, here a rectangular seal of circular section, arranged so that when the movable cover 21 is in the position of closing the opening 22, the seal 86 defines at least partially with the movable cover (in the present case, the end 50.1 of the slide 50) a closed enclosure 87 which extends around the diode 81 and an active portion of the target 83.

[0056] The transceiver 80 is connected to a processing unit 90 of the avionics system of the aircraft on which the nacelle 1 is mounted. The transceiver 80 and the reflective target 83 constitute a distance measuring device 91.

[0057] In operation, the transceiver 80 emits a laser flux 82 to the reflective target 83. The processing unit 90 analyzes the time taken by the laser flux 82 to travel the distance separating the transceiver 80—which constitutes a first measurement point secured to the fixed upstream cover 20 (here the rail 61)—and the reflective target 83—which constitutes a second measurement point—and to return to the transceiver 80. On the basis of the measured time, the processing unit 90 calculates and returns to the avionics system a value of the distance separating the transceiver 80 and the reflective target 83 on the principle of telemetric measurement by time of flight measurement.

[0058] FIXED GRILLS

[0059] Elements identical or analogous to those previously described will bear a numerical reference identical to this in the following description of a second and a third embodiment of the invention.

[0060] According to a second embodiment shown in [Fig.9] to 12, the thrust reverser 100 is here of the “fixed grid” type and comprises two sets of grids 40, and 41 in the form of a half-cylinder secured to the structure 2 of the nacelle 1. Each set of grids 40 and 41 extends into the housing 11 when the cowl 21 is in its position for closing the opening 22 (figures 9-10). The housing 11 is, according to the second embodiment, defined by an internal wall 23 and an external wall 24 of the cowl 21. In a manner known per se, the thrust reverser 100 comprises a diverter door 25 articulated on an arm 26.

[0061] The sliders 50 to 53 of the guide device of the hood 21 are, in this second embodiment, integral with the hood 21 and cooperate respectively with the rails 61, 67, 69, and 75 integral with the structure 2 of the nacelle 1.

[0062] The transceiver 80 is located downstream of the set of grids 40 and is integral with the structure of the nacelle 1. The reflective target 83 is integral with the cover 21. As visible in FIGS. 9 and 11, the transceiver 80 extends into the internal housing 11 of the cover 21 as well as the laser flux 82. The housing 11 thus constitutes a volume for protecting the distance measuring device 91 against the flux 16 and the environment outside the turbojet 3. The seal 86 makes it possible, when the cover 21 is in the configuration for closing the opening 22 ([Fig. 8]), to protect the transceiver 80 and the active portion of the target 83 from the external environment (dust and humidity).

[0063] According to a third embodiment shown in figures 13 and 16, the thrust reverser 100 is of the “fixed grid” type in which the sliders 50 to 53 of the guide device of the cowl 21 are integral with the cowl 21 and cooperate respectively with the rails 61, 67, 69, and 75 integral with the structure 2 of the nacelle 1.

[0064] The transceiver 80 is located near the upstream end of the grid assembly 40 and is secured to the rail 61. The reflective target 83 is positioned on the upstream end 50.1 of the slider 50. As visible in FIGS. 15 and 16, the laser flux 82 extends in the rail 61, more particularly between the wings 61.2 and 61.3. Here too, the seal 86 makes it possible, when the cover 21 is in the configuration for closing the opening 22 ([Fig. 10]), to protect the transceiver 80 and the active portion of the target 83 from the external environment (dust and humidity). Thus, the second measurement point—here the reflective target 83—is located on the slider 50.

[0065] All of the embodiments detailed above comprise a measuring device 91 which is positioned close to one of the guide rails 61, 63, 65 or 67. For the purposes of the present application, a guide device is located close to one of the guide rails if one of its measuring points is arranged less than fifty centimeters away from said guide rail.

[0066] The operation of the distance sensor according to the second and third embodiments is identical to the first embodiment.

[0067] Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0068] In particular,

[0069] - although here the thrust reverser comprises four cylinders, the invention applies also to other configurations of actuation of the movable hood such as for example a single actuator, two, three or more than four;

[0070] - although here the thrust reverser comprises a hydraulic cylinder, the invention also applies to other types of actuators such as electric or pneumatic actuators, linear or not;

[0071] - although here the groove of the guide rail is dovetail-shaped, the invention also applies to other types of grooves such as polyhedral or circular section grooves;

[0072] - although here the thrust reverser comprises a laser diode, the invention applies to other types of device for measuring a distance between two points, such as a cable reel device with a drum equipped with a rotary encoder or to other types of wave flux transmitter, such as an emitter of an ultrasonic or infrared flux or of a magnetic or radio wave (radar type) or any optical sensor (camera, LIDAR);

[0073] - although here the distance measuring device performs the distance measurement on the principle of telemetric measurement by time-of-flight measurement, the invention also applies to other measurement principles such as for example laser measurement by interferometry or measurement by triangulation;

[0074] - although, in its application to a moving grid system in which the grid is integral with the cover, the reflective target is integral with the grid, the invention also applies to other locations of the second measuring point on the movable cover such as for example an location on the internal or external wall of the cover;

[0075] - although here the thrust reverser comprises four cylinders distributed at four- ninety degrees from each other, the invention also applies to other types of actuator installation such as for example two cylinders at one hundred and eighty degrees, three or more than four jacks.

Claims

Claims

1. A thrust reverser (100) capable of adopting a so-called direct jet configuration and a so-called thrust reversal configuration, the thrust reverser (100) comprising: - a fixed structure (20) and a movable structure (21) mounted opposite an opening (22) delimited between the fixed structure (20) and an upstream end of a movable cowl of the movable structure (21) when the thrust reverser (100) is in the thrust reversal configuration; - an actuator (30-33) for selectively moving the movable structure (21) between the direct jet position in which the opening (22) is closed and the thrust reversal position in which the opening (22) is uncovered;wherein, the thrust reverser (100) comprises a device (91) for measuring a distance between a first measuring point and a second measuring point which is integral with the mobile structure (21), and one of the measuring points comprises an emitter (80) of a wave flux (82) and the other of the measuring points comprises a reflecting element (83) of at least a part of the wave flux (82), the thrust reverser (100) comprising a seal (86) which, when the mobile structure (21) is in the position of closing the opening (22), defines at least partially with the mobile structure (21) a closed enclosure which extends around the first measuring point and the second measuring point;

2. Thrust reverser (100) according to claim 1, wherein the measuring device (91) is of the telemetric type by measuring the flight time.

3. 3. Thrust reverser (100) according to any one of claims 1 to 2, comprising a sliding guide device for the movable structure (21), the guide device comprising at least one guide rail (61, 63, 65, 67).

4. 4. Thrust reverser (100) according to claim 3, in which the guide device comprises a slider (50-53) integral with a set of grids (40-41) linked to the mobile structure (21) and which cooperates with the guide rail (61, 63, 65, 67), the second measuring point being located on the slide (50-53).

5. 5. Thrust reverser (100) according to any one of claims 1 to 4, comprising a grid (40-43) integral in translation with the mobile structure (21) and which extends in a grid housing (11) when the mobile structure (21) is in its closed position, the first measurement point being located in the grid housing (11).

6. 6. Thrust reverser (100) according to one of claims 3 to 5, wherein the measuring device (91) is arranged so that the wave flow (82) extends in a volume partially delimited by a core (61.1) and a wing (61.2, 61.3) of the guide rail (61).

7. 7. Thrust reverser (100) according to any one of claims 1 to 6, wherein the first measuring point and the second measuring point are arranged to be contained in a protective volume (11) defined at least partially by the mobile structure (21), when the mobile structure (21) is in its closed position, but also when the mobile structure (21) is in its released position, as well as during the transit of the mobile structure (21) between these two positions.

8. 8. Nacelle (1) comprising a thrust reverser (100) according to any one of claims 1 to 7.

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