Reverse thrust device with improved reliability

Abstract

The invention relates to a 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 flow position and a reverse thrust position; wherein the thrust reverser (100) comprises means (91) for measuring the distance between a first measurement point and a second measurement point rigidly connected to the movable structure (21), and one measurement point comprises an emitter (80) of a wave flow (82) and the other measurement point comprises a reflective element (83) of at least part of the wave flow (82).

Description

[0001] Specification Background Art

[0003] The aircraft is driven by a plurality of turbojet engines, each turbojet engine being mounted in a nacelle which also houses a set of auxiliary drive devices related to the operation of the engine and which perform various functions when the turbojet engine is running or stopped. These auxiliary drive devices include in particular a thrust reverser system, also known as a thrust reverser.

[0004] The nacelle generally has a tubular structure, including an air intake upstream of the turbojet engine, an intermediate part for surrounding the turbojet engine fan, a downstream part integrating the thrust reverser and for surrounding the turbojet engine combustion chamber, and generally ending with a nozzle located downstream of the turbojet engine.

[0005] Modern nacelles are used to house ducted turbojet engines which are capable of generating a hot air flow (main stream) and a cold air flow (secondary stream) by means of rotating fan blades. The cold air flow circulates outside the turbojet engine through an annular channel (also known as an air flow path) formed between the turbojet engine fairing and the inner wall of the nacelle. These two air flows are ejected from the turbojet engine through the rear of the nacelle.

[0006] The function of the thrust reverser is to increase the braking capacity of the aircraft during landing by deflecting at least a part of the air flow ejected from the turbojet engine towards the front. At this stage, the thrust reverser blocks at least a part of the cold air flow path and deflects this air flow towards the front of the nacelle, thus generating a reverse thrust which is superimposed on the braking force of the aircraft wheels.

[0007] Traditional thrust reverser systems include a cowl which is slidably mounted opposite an opening which at least partially delimits the air flow of the turbojet engine. This opening is used to allow the deflected air flow to pass through and is sealed by an outer cowl when the nacelle is operating in a direct jet configuration. When operating in a reverse jet configuration, the cowl opens the opening by means of a cylinder-type linear actuator for moving the cowl. The deflector can also be activated. The cylinder extends upstream of the opening, generally between the fixed part of the nacelle and the frame of the cowl.

[0008] The aircraft computer requires information about the position and / or the open state of the cowl. This information is generally provided by an encoder mounted on the cylinder. This is generally a rotary encoder which, in the case of an electric gear motor actuator, measures the number of revolutions of a screw connected to the outlet of the piston rod. Hydraulic cylinders generally integrate a linear displacement sensor of the linear variable differential transformer (LVDT) type for measuring the extended length of the piston rod.

[0009] Direct measurements on the actuator can use sensors that are not affected by external conditions. However, to obtain precise position information (millimeter-level accuracy of the position of the movable cowl), high-precision sensors and associated kinematic chains are required, especially to reduce clearances. Such a setup incurs very high equipment manufacturing costs and instrumentation costs. Installing the cylinder and its sensors also requires expensive adjustment and calibration operations.

[0010] Due to the same adjustment and calibration operations, the installation, replacement / repair time and costs of the sensors and the cylinder increase.

[0011] If the kinematic chain connecting the cylinder and the cowl breaks or malfunctions, incorrect reverse thrust device status information may be generated and undetected.

[0012] Finally, the currently used sensors have a significant impact on cost and weight, which is particularly attributed to the measurement technology used (LVDT) and the arrangements required to ensure electromagnetic compatibility of the sensors with the aircraft environment.

[0013] Field of the Invention

[0014] The object of the present invention is to improve the reliability of the measurement of the position of the cowl of the reverse thrust system. Summary of the Invention

[0015] To this end, the present invention proposes a reverse thrust device that can adopt a so-called direct jet configuration and a so-called reverse thrust configuration. The reverse thrust device includes a fixed structure and a movable structure. When the reverse thrust device is in the reverse thrust configuration, the movable structure is mounted opposite an opening defined between the fixed structure and the upstream end of the movable cowl of the movable structure; and an actuator for selectively moving the movable structure between a direct jet position where the opening is sealed and a reverse thrust position where the opening is opened. According to the present invention, the reverse thrust device includes means for measuring the distance between a first measurement point and a second measurement point rigidly connected to the movable cowl. One of the measurement points includes a wave current emitter, and the other measurement point includes a reflecting element for at least part of the wave current.

[0016] This forms a reverse thrust system that directly measures the position and state of the movable cowl on the sliding cowl, providing reliable and direct status information that is independent of the accuracy or state of the kinematic chain connecting the actuator and the sliding cowl. The installation, maintenance, and replacement of such sensors are fast and do not require recalibration of the motion actuator chain.

[0017] According to other specific, non-exclusive, and optional embodiments of the present invention:

[0018] · The measuring means is a telemetry device using time-of-flight measurement.

[0019] The system includes a seal which, when the movable structure is in a position to seal the opening, at least partially delimits with the movable structure an enclosed housing that extends around a first measurement point and a second measurement point.

[0020] The system includes means for slidably guiding a movable cowl, the means including at least one guide rail.

[0021] The system includes vanes rigidly connected to the movable structure so as to translate therewith, which vanes extend into vane grooves when the movable structure is in the sealing position, and the first measurement point is located in the vane grooves.

[0022] The guiding means includes sliders rigidly connected to a set of vanes connected to the movable structure and cooperating with the guide rail, and the second measurement point is located on the sliders.

[0023] The measuring means is arranged such that the wave current extends in a space defined by the web and flange portions of the guide rail.

[0024] The first measurement point and the second measurement point are arranged to be included in a protection space at least partially delimited by the movable structure when the movable structure is in the sealing position, the open position, and when transitioning between these two positions.

[0025] The invention also applies to a nacelle including the above reverse thrust device.

[0026] Other features and advantages of the invention will become apparent by reading the following description of specific non - limiting embodiments of the invention. Brief Description of the Drawings

[0028] The invention will be better understood by reading the following description given as a non - limiting example and by referring to the drawings, which show:

[0029] Figure 1 is a schematic semi - cross - sectional view of a turbojet engine equipped with a reverse thrust device according to a first embodiment of the invention in a so - called "direct jet" configuration;

[0030] Figure 2 is Figure 1 a detailed partial schematic semi - cross - sectional view of the reverse thrust device of the turbojet engine in ;

[0031] Figure 3 is a partial schematic semi - cross - sectional view of the reverse thrust device according to a first embodiment of the invention in a so - called "lateral jet" reverse thrust configuration;

[0032] Figure 4 is a schematic front view of a turbojet engine according to the invention;

[0033] Figure 5 is equipped with Figure 1Schematic bottom view of a turbofan engine with reverse thrust device;

[0034] Figure 6 is Figure 4 Perspective close-up view of the reverse thrust device of a turbofan engine;

[0035] Figure 7 is similar to Figure 6 Partial perspective close-up view;

[0036] Figure 8 is Figure 1 Close-up view of the distance measuring device of the reverse thrust device;

[0037] Figure 9 is a schematic half-sectional view of a turbofan engine equipped with a reverse thrust device according to the second embodiment of the present invention in the so-called "direct jet" configuration;

[0038] Figure 10 is Figure 9 Partial schematic top view of a turbofan engine;

[0039] Figure 11 is Figure 9 Schematic half-sectional view of a turbofan engine in the so-called "lateral jet" reverse thrust configuration;

[0040] Figure 12 is Figure 11 Partial schematic top view of a turbofan engine;

[0041] Figure 13 is a schematic half-sectional view of a turbofan engine equipped with a reverse thrust device according to the third embodiment of the present invention in the so-called "direct jet" configuration;

[0042] Figure 14 is Figure 13 Partial schematic top view of a turbofan engine;

[0043] Figure 15 is Figure 13 Schematic half-sectional view of a turbofan engine in the so-called "lateral jet" reverse thrust configuration;

[0044] Figure 16 is Figure 15 Partial schematic top view of a turbofan engine.

[0045] In these figures, from one figure to another, the same reference numerals denote the same or similar elements. In addition, for clarity, the drawings are not drawn to scale unless otherwise stated.

[0046] Description of the embodiment

[0047] ReferenceFigures 1 to 8 , the nacelle 1 includes a structure 2 extending around a turbojet engine 3, the rotating elements of the turbojet engine 3 being rotatably mounted about a longitudinal axis Ax. Air is drawn in at an upstream portion 3.1 of the turbojet engine 3 and discharged through a downstream portion 3.2 of the turbojet engine.

[0048] In the present text, the terms "upstream" and "downstream" refer to the position or direction of an element according to the direction of the air flow in the turbojet engine, and the terms "inner" or "inside" and "outer" or "outside" refer to the position or direction relative to the longitudinal axis Ax. The structure 2 includes an outer fairing 10, which includes an inner groove 11, which in this case is delimited by an inner wall 12 and an outer wall 13. The inner wall 12 defines an outer partition 14, which delimits a flow path 15 for the air flow 16 of the turbojet engine 3.

[0049] The nacelle 1 includes a thrust reverser 100, which includes a cylindrical fixed upstream cowl 20 and a movable downstream cowl 21, the downstream cowl 21 being movably mounted on a slide in a direction parallel to the axis Ax, opposite to an annular radial opening 22 made in the partition 14.

[0050] The thrust reverser 100 also includes four hydraulic cylinders 30, 31, 32 and 33 for selectively moving the cowl 21 between a position in which the cowl 21 seals the opening 22 ( Figure 1 ) and a position in which the opening 22 is opened ( Figure 2 ). The hydraulic cylinders 30 to 33 extend parallel to the longitudinal axis Ax and are distributed around the perimeter of the nacelle 1 at 90 degrees intervals from each other. A deflector door 25, known per se, is hinged by an arm 26 and, when the opening 22 is open, the deflector door 25 can be in a position in which it deflects the air flow 16 ( Figure 3 ).

[0051] Movable cascade vanes

[0052] In this case, the thrust reverser 100 is of the "movable cascade vane" type and includes two sets of semi-cylindrical vanes 40 and 41, which are rigidly connected to the cowl 21 so as to translate therewith. When the cowl 21 is in the position in which it seals the opening 22, each set of vanes 40 and 41 extends into the groove 11 ( Figure 1 and Figure 3 ). The vane set 40 includes an upper left slide 50, which cooperates with a dovetail upper left groove 60 in an upper left guide rail 61 rigidly connected to the fixed upstream cowl 20. The vane set 40 also includes a lower left slide 51, which cooperates with a similarly dovetail lower left groove 62 in a lower left guide rail 63.

[0053] As Figure 4As shown, the guide rail 61 has a web 61.1, from which a upper flange 61.2 and a lower flange 61.3 project to define a left upper groove 60. The blade group 41 is similar to the blade group 40. Thus, the blade group 41 includes a right upper slider 52, which cooperates with a dovetail-shaped right upper groove 64 in the right upper guide rail 65, and a right lower slider 53, which cooperates with a dovetail-shaped left lower central groove 66 in the left lower central guide rail 67.

[0054] The guide rails 61, 63, 65 and 67 together with the sliders 50 to 53 form a device for guiding the cover 21.

[0055] As Figure 4 and Figure 5 shown, when the cover 21 is in the position of opening the opening 22, the blade assemblies 40 and 41 respectively extend opposite two substantially less than 124-degree fan-shaped regions of the opening 22. Thus, the blade group 40 extends opposite the left fan-shaped region 22.1 of the opening 22, and the blade group 41 extends opposite the right fan-shaped region 22.2 of the opening 22.

[0056] Since all the blades are the same, only the features related to the blade group 40 will be described now, and these features also apply to the blade group 41.

[0057] As Figure 7 shown, the thrust reverser 100 includes a transceiver 80, which is equipped with a diode 81 arranged to emit a laser beam 82 towards a reflection target 83 located on the upstream end 50.1 of the slider 50. In this case, the end 50.1 extends in a transverse plane P perpendicular to the axis Ax. As Figure 2 , Figure 3 and Figure 7 shown, the transceiver 80 is connected to a bracket 84 rigidly connected to an extension 85 of the guide rail 61. When the cover 21 moves to the position of opening the opening 22, the laser beam 82 extends in the guide rail 61, more specifically between the flanges 61.2 and 61.3. The transceiver 80 includes a seal 86, which is in this case a rectangular seal with a circular cross-section, arranged such that when the movable cover 21 is in the position of sealing the opening 22, the seal 86 and the movable cover (in the current case, the end 50.1 of the slider 50) at least partially define a closed housing 87 extending around the active part of the diode 81 and the target 83. The transceiver 80 is connected to a processing unit 90 of the avionics system of the aircraft on which the nacelle 1 is installed. The transceiver 80 and the reflection target 83 constitute a ranging device 91.

[0058] In operation, the transceiver 80 emits a laser beam 82 towards the reflecting target 83. The processing unit 90 analyzes the time required for the laser beam 82 to travel from the transceiver 80 (constituting a first measurement point rigidly connected to the fixed upstream cowl 20, in this case connected to the rail 61) to the reflecting target 83 (constituting a second measurement point) and back to the transceiver 80. Based on the measured time, the processing unit 90 calculates and returns to the avionics system a distance value between the transceiver 80 and the reflecting target 83 according to the telemetry principle of time-of-flight measurement.

[0059] Fixed cascade vanes

[0060] In the description of the second and third embodiments of the present invention given below, elements that are the same or similar to those above have the same reference numerals.

[0061] According to Figures 9 to 12 the second embodiment shown, in this case, the thrust reverser 100 is of the "fixed cascade vane" type and includes two sets of semi-cylindrical vanes 40 and 41 which are rigidly connected to the structure 2 of the nacelle 1. When the cowl 21 is in the position of sealing the opening 22, each set of vanes 40 and 41 extends into the recess 11 ( Figures 9 - 10 ). According to the second embodiment, the recess 11 is defined by the inner wall 23 and the outer wall 24 of the cowl 21. In a manner known per se, the thrust reverser 100 includes a deflector door 25 hinged by an arm 26.

[0062] In this second embodiment, the sliders 50 to 53 of the means for guiding the cowl 21 are rigidly connected to the cowl 21 and cooperate respectively with the rails 61, 67, 69 and 75 rigidly connected to the structure 2 of the nacelle 1.

[0063] The transceiver 80 is located downstream of the vane set 40 and is rigidly connected to the structure of the nacelle 1. The reflecting target 83 is rigidly connected to the cowl 21. As Figure 9 and Figure 11 shown, the transceiver 80 and the laser beam 82 extend into the inner recess 11 of the cowl 21. Thus, the recess 11 constitutes a space for protecting the distance measuring device 91 from the influence of the air flow 16 and the external environment of the turbojet engine 3. When the cowl 21 is in the configuration of sealing the opening 22 ( Figure 8 ), the seal 86 makes it possible to protect the active parts of the transceiver 80 and the target 83 from the external environment (dust and moisture).

[0064] According to Figure 13 and Figure 16 the third embodiment shown, the thrust reverser 100 is of the "fixed cascade vane" type, wherein the sliders 50 to 53 of the means for guiding the cowl 21 are rigidly connected to the cowl 21 and cooperate respectively with the rails 61, 67, 69 and 75 rigidly connected to the structure 2 of the nacelle 1.

[0065] The transceiver 80 is located near the upstream end of the blade group 40 and is rigidly connected to the guide rail 61. The reflection target 83 is positioned on the upstream end 50.1 of the slider 50. As Figure 15 and Figure 16 shown, the laser beam 82 extends in the guide rail 61, more specifically between the flanges 61.2 and 61.3. Similarly, when the cover 21 is in the configuration of sealing the opening 22 ( Figure 10 ), the seal 86 enables protection of the active parts of the transceiver 80 and the target 83 from the external environment (dust and moisture). Thus, the second measurement point (in this case the reflection target 83) is located on the slider 50.

[0066] All of the above embodiments include a measuring device 91, which is located near one of the guide rails 61, 63, 65 or 67. For the purposes of the present application, a guiding device is located near one of the guide rails if one measurement point of the guiding device is arranged at a position less than fifty centimeters from the said guide rail.

[0067] The operation of the distance sensor according to the second and third embodiments is the same as that of the first embodiment.

[0068] It goes without saying that the present invention is not limited to the described embodiments, but encompasses any alternative embodiments falling within the scope of the present invention defined by the claims.

[0069] In particular:

[0070] · Although in this case the thrust reverser device includes four cylinders, the present invention is also applicable to other drive configurations of the movable cover, such as a single actuator, or two, three or more than four actuators;

[0071] · Although in this case the thrust reverser device includes a hydraulic cylinder, the present invention is also applicable to other types of actuators, such as electric or pneumatic actuators, which may be linear or non-linear;

[0072] · Although in this case the groove in the guide rail is dovetail-shaped, the present invention is also applicable to other types of grooves, such as grooves having a polyhedral or circular cross-section;

[0073] · Although in this case the thrust reverser device includes a laser diode, the present invention is applicable to other types of devices for measuring the distance between two points, such as a cable reel device equipped with a rotary encoder, or other types of wave current emitters, such as infrared ultrasonic current emitters, magnetic wave or radio wave (radar type) emitters or any optical sensors (cameras, lidars);

[0074] · Although in this case the distance measuring device measures the distance based on the telemetry principle of time-of-flight measurement, the present invention is also applicable to other measurement principles, such as laser interferometry or triangulation;

[0075] · Although in its application to the moving cascade vane system, the vane is rigidly connected to the shroud, and the reflection target is rigidly connected to the vane, the present invention is also applicable to other ways of arranging the second measurement point on the movable shroud, such as arranging it on the inner wall or outer wall of the shroud;

[0076] · Although in this case the thrust reverser device includes four cylinders distributed at 90-degree intervals from each other, the present invention is also applicable to other types of actuator arrangements, such as two cylinders spaced 180 degrees apart, three cylinders, or more than four cylinders.

Claims

1. A thrust reverser device (100) capable of adopting a so-called direct jet configuration and a so-called thrust reverse configuration, the thrust reverser device (100) comprises: a fixed structure (20) and a movable structure (21), when the thrust reverser device (100) is in the thrust reverse configuration, the movable structure (21) is installed opposite an opening (22) defined between the fixed structure (20) and the free end on the movable cover of the movable structure (21); actuators (30 - 33) for selectively moving the movable structure (21) between a direct jet position where the opening (22) is sealed and a thrust reverse position where the opening (22) is opened; wherein, the thrust reverser device (100) includes means (91) for measuring the distance between a first measurement point and a second measurement point rigidly connected to the movable structure (21), and one measurement point includes a transmitter (80) of a wave current (82), and the other measurement point includes a reflection element (83) of at least part of the wave current (82), the thrust reverser device (100) includes a seal (86), when the movable structure (21) is in a position to seal the opening (22), the seal (86) and the movable structure (21) at least partially define an enclosed housing extending around the first measurement point and the second measurement point.

2. The thrust reverser device (100) according to claim 1, wherein, the measuring means (91) is a telemetry device using time - of - flight measurement.

3. The thrust reverser device (100) according to any one of claims 1 to 2, including means for slidably guiding the movable structure (21), the guiding means including at least one guide rail (61, 63, 65, 67).

4. The thrust reverser device (100) according to claim 3, wherein, the guiding means includes sliders (50 - 53) rigidly connected to a set of blades (40 - 41) connected to the movable structure (21) and cooperating with the guide rails (61, 63, 65, 67), and the second measurement point is located on the sliders (50 - 53).

5. The thrust reverser device (100) according to any one of claims 1 to 4, including blades (40 - 43) rigidly connected to the movable structure (21) so as to translate therewith, when the movable structure (21) is in the sealed position, the blades extend into a blade groove (11), and the first measurement point is located in the blade groove (11).

6. The thrust reverser device (100) according to any one of claims 3 to 5, wherein, the measuring means (91) is arranged such that the wave current (82) extends in a space partially defined by the web (61.1) and flanges (61.2, 61.3) of the guide rail (61).

7. The thrust reverser device (100) according to any one of claims 1 to 6, wherein, the first measurement point and the second measurement point are arranged such that when the movable structure (21) is in the sealed position, the open position, and during the transition between these two positions, they are both included in a protection space (11) at least partially defined by the movable structure (21).

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

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