Patent Publication Number: US-2019178206-A1

Title: Jet engine comprising a nacelle equipped with a thrust reversing system comprising doors

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of the French patent application No. 1761820 filed on Dec. 8, 2017, the entire disclosures of which are incorporated herein by way of reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a dual flow jet engine which comprises a nacelle equipped with a thrust reversing system comprising doors, an aircraft comprising at least one such dual flow jet engine, and a method for displacing the thrust reversing system in such a dual flow jet engine. 
     BACKGROUND OF THE INVENTION 
     An aircraft comprises a fuselage, on each side of which is fixed a wing. Under each wing, there is suspended at least one dual flow jet engine with a secondary jet. Each dual flow jet engine is fixed under the wing via a pylon which is fixed between the structure of the wing and the structure of the dual flow jet engine. 
     The dual flow jet engine comprises an engine and a nacelle which is fixed around the engine. 
     The nacelle comprises a thrust reversing system which comprises a plurality of outer doors, each being rotationally mobile on the structure of the nacelle between a stowed position in which it comes into continuity with the outer surface of the nacelle and an outward deployed position in which it opens a window in the wall of the nacelle to expel the air of the secondary flow to the outside of the nacelle. 
     Some thrust reversing systems also include inner doors, in which each is mobile between a stowed position in which it is pressed against an inner surface of the nacelle around the secondary jet, and a deployed position in which it is positioned across the secondary jet to direct the secondary flow towards the window. 
     Currently, the displacement of the inner and outer doors requires a relatively complex maneuvering system and it is necessary to find a different mechanism. 
     SUMMARY OF THE INVENTION 
     One object of the present invention is to propose a dual flow jet engine which comprises a nacelle equipped with a thrust reversing system with a plurality of doors and with a different opening/closing mechanism. 
     To this end, a dual flow jet engine is proposed comprising an engine, a nacelle surrounding the engine and a fan casing, in which a secondary jet of a secondary flow is delimited between the nacelle and the engine and in which an air flow circulates in a direction of flow, the nacelle comprising:
         a fixed structure attached to the fan casing,   a thrust reversing system having:   a mobile assembly having a mobile cowl and a frame, the mobile cowl being fixed to and downstream of the frame relative to the direction of flow, the mobile assembly being translationally mobile on the fixed structure in a direction of translation between an advanced position in which the mobile assembly is positioned in such a way that the mobile cowl is close to the fan casing and a retracted position in which the mobile assembly is positioned in such a way that the mobile cowl is at a distance from the fan casing to define between them an open window between the secondary jet and the outside of the nacelle,   a plurality of pairs of doors arranged inside the nacelle, each pair being formed by an inner door and an outer door arranged facing the inner door, each door being mounted articulated by a downstream edge, relative to the direction of flow, on the frame between a stowed position in which it blocks a zone of the window and a deployed position in which it does not block the zone of the window, the inner doors extending towards the engine in a deployed position, the outer doors extending outwards from the nacelle in the deployed position and being arranged between the mobile cowl and the fixed structure in the stowed position so as to form an outer wall of the nacelle,   for each pair of doors, a runner associated with the pair of doors, the runner being mounted to be translationally mobile parallel to the direction of translation on the frame between a first position and a second position, in which the switching from the stowed position to the deployed position of each door of the pair is mechanically associated with the switching of the runner from the first position to the second position and vice versa, and   for each runner, a second actuator provided to ensure the translational displacement of the runner from the first position to the second position and vice versa, and   at least one first actuator provided to ensure the translational displacement of the frame from the advanced position to the retracted position and vice versa.       

     Such a jet engine makes it possible to simplify the mechanism actuating the thrust reversing system and to dissociate the displacement of the mobile assembly from the displacement of the doors. 
     Advantageously, the thrust reversing system further comprises, for each runner, a first transmission system provided to switch the inner door associated with the runner from the stowed position to the deployed position simultaneously with the switching of the runner from the first position to the second position and vice versa, and, for each runner, a second transmission system provided to switch the outer door associated with the runner from the stowed position to the deployed position simultaneously with the switching of the runner from the first position to the second position and vice versa. 
     Advantageously, each actuator takes the form of an electric ball jack. 
     Advantageously, the nacelle comprises at least one baffle plate arranged around the secondary jet at the entry of the window. 
     The invention also proposes an aircraft comprising at least one dual flow jet engine according to one of the preceding variants. 
     The invention also proposes a displacement method for a thrust reversing system according to one of the preceding variants and comprising, from the advanced position of the mobile assembly, from the stowed positions of the inner and outer doors, from the first position of the runners:
         a first activation step during which each first actuator is activated to ensure the translational displacement of the mobile assembly from the advanced position to the retracted position, then   a second activation step during which each second actuator is activated to ensure the translational displacement of the associated runner from the first position to the second position, then   a third activation step during which each second actuator is activated to ensure the translational displacement of the associated runner from the second position to the first position, then   a fourth activation step during which each first actuator is activated to ensure the translational displacement of the mobile assembly from the retracted position to the advanced position.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features of the invention mentioned above, and others, will become more clearly apparent on reading the following description of an exemplary embodiment, the description being given in relation to the attached drawings, in which: 
         FIG. 1  is a side view of an aircraft comprising a dual flow jet engine according to the invention, 
         FIG. 2  is a perspective and interior view of a part of a nacelle of the dual flow jet engine according to the invention, 
         FIG. 3  is a schematic and cross-sectional representation of a thrust reversing system according to the invention in the stowed position, 
         FIG. 4  is a representation similar to that of  FIG. 3  for an intermediate position, 
         FIG. 5  is a representation similar to that of  FIG. 3  for a deployed position, 
         FIG. 6  shows an outside view of the thrust reversing system, and 
         FIG. 7  represents a functional diagram of a displacement method for a thrust reversing system according to the invention. 
     
    
    
     DETAILED EXPLANATION OF EMBODIMENTS 
     In the following description, the terms relating to a position are taken with reference to the direction of flow of the air in a jet engine which therefore flows from forward to aft of the aircraft while the aircraft is moving forwards. 
       FIG. 1  shows an aircraft  10  which comprises a fuselage  12 , on each side of which is fixed a wing  14  which bears at least one dual flow jet engine  100  according to the invention. The dual flow jet engine  100  is fixed under the wing  14  via a pylon  16 . 
     The dual flow jet engine  100  has a nacelle  102 , an engine which is housed inside the nacelle  102  in the form of a core and a fan casing  206   a  forward of the nacelle  102 . 
     In the following description, and by convention, X denotes the longitudinal axis of the dual flow jet engine  100  which is parallel to the longitudinal axis of the aircraft  10 , or roll axis, oriented positively towards the front of the aircraft  10 , Y denotes the transverse axis which is parallel to the pitch axis of the aircraft which is horizontal when the aircraft is on the ground, and Z denotes the vertical axis which is parallel to the yaw axis when the aircraft is on the ground, these three directions X, Y and Z being mutually orthogonal and forming an orthonormal reference frame. 
       FIG. 2  shows a part of the nacelle  102  and  FIGS. 3 to 5  show different positions of a thrust reversing system  250  of the nacelle  102 .  FIG. 6  shows an outside view of the thrust reversing system  250  in the deployed position, but without the doors of the thrust reversing system  250 . 
     The dual flow jet engine  100  has, between the nacelle  102  and the engine, a secondary jet  202  in which the secondary flow  208  circulates originating from the air inlet through the fan and which therefore flows in the direction of flow which goes from upstream to downstream. 
     The nacelle  102  has a fixed structure  206  which is mounted fixed on the fan casing  206   a.    
     The thrust reversing system  250  has a mobile assembly  207  which comprises a mobile cowl  207   a  forming the walls of the nozzle and a frame  207   b . The frame  207   b  here takes the form of a cylinder with openwork walls. The mobile cowl  207   a  is fixed to and downstream of the frame  207   b  relative to the direction of flow. 
     The mobile assembly  207 , via the frame  207   b , is mounted to be translationally mobile in a direction of translation that is overall parallel to the longitudinal axis X on the fixed structure  206  of the nacelle  102 , and more particularly here on the 12 o&#39;clock beam and the 6 o&#39;clock beam. 
     The translation of the frame  207   b , and therefore of the mobile assembly  207 , is produced by any appropriate guide systems such as, for example, guides between the fixed structure  206  and the frame  207   b.    
     The mobile assembly  207 , and therefore the frame  207   b , is mobile between an advanced position ( FIG. 3 ) and a retracted position ( FIGS. 4, 5 and 6 ) and vice versa. In advanced position, the mobile assembly  207 , and therefore the frame  207   b , is positioned as far as possible forward relative to the direction of flow so that the mobile cowl  207   a  is close to the fan casing  206   a . In retracted position, the mobile assembly  207 , and therefore the frame  207   b , is positioned as far aft as possible relative to the direction of flow so that the mobile cowl  207   a  is at a distance from the fan casing  206   a.    
     In the advanced position, the mobile cowl  207   a  and the fan casing  206   a  are in continuation so as to define the outer surface of the secondary jet  202 . 
     In the retracted position, the mobile cowl  207   a  and the fan casing  206   a  are at a distance and define between an open window  210  between the secondary jet  202  and the outside of the nacelle  102 . That is to say that the air originating from the secondary flow  208  passes through the window  210  to re-emerge outside the dual flow jet engine  100 . 
     The fan casing  206   a  delimits the window  210  upstream relative to the longitudinal axis X and the mobile cowl  207   a  delimits the window  210  downstream relative to the longitudinal axis X. 
     The nacelle  102  comprises a plurality of inner doors  104  distributed over the periphery and inside the nacelle  102  as a function of the angular aperture of the window  210  about the longitudinal axis X. 
     Each inner door  104  is mounted articulated on the frame  207   b  between a stowed position ( FIGS. 3 and 4 ) and a deployed position ( FIG. 5 ) and vice versa. The switching from the stowed position to the deployed position is performed by a rotation of the inner door  104  towards the inside of the jet engine  100 . 
     The stowed position of the inner doors  104  can be adopted when the frame  207   b  is in advanced position or in retracted position. The deployed position of the inner doors  104  can be adopted only when the frame  207   b  is in retracted position. 
     In the stowed position, each inner door  104  blocks a zone of the openwork part of the frame  207   b  when the latter is in advanced position and the same zone of the openwork part of the frame  207   b  and a zone of the window  210  when the frame  207   b  is in the retracted position. In the deployed position, the inner door  104  does not block the zone of the window  210  or the openwork part of the frame  207   b  allowing passage of the secondary flow  208  and the inner door  104  extends towards the engine, that is to say across the secondary jet  202 . 
     Thus, in the stowed position, each inner door  104  is overall in the extension of the mobile cowl  207   a  and in the deployed position, each inner door  104  is positioned across the secondary jet  202  and deflects at least a part of the secondary flow  208  to the outside through the window  210 , the flow is oriented forwards using outer doors  105  that make it possible to produce a counter-thrust and that are described herein below. 
     In advanced position, each inner door  104  is positioned outside the fan casing  206   a.    
     Each inner door  104  is articulated by a downstream edge, relative to the direction of flow, at the downstream part of the frame  207   b  on hinges  212  that are fixed to the frame  207   b  whereas the opposite free edge is positioned upstream in the stowed position and towards the engine in the deployed position. 
     The thrust reversing system  250  also comprises, for each inner door  104 , an outer door  105 . The outer doors  105  are distributed over the periphery and on the outside of the nacelle  102  as a function of the angular aperture of the window  210  about the longitudinal axis X. The outer doors  105  are arranged outside relative to the inner doors  104 . Each outer door  105  is mounted facing an inner door  104  and the outer door  105  and the facing inner door  104  constitute a pair of doors. The thrust reversing system  250  thus comprises a plurality of pairs of doors  104 ,  105  arranged inside the nacelle  102 . 
     Each outer door  105  is mounted articulated on the frame  207   b  between a stowed position ( FIGS. 3 and 4 ) and a deployed position ( FIG. 5 ) and vice versa. The switching from the stowed position to the deployed position is performed by a rotation of the outer door  105  towards the outside of the jet engine  100 . The articulations of the outer doors  105  are overall facing the articulations of the inner doors  104 , as is shown in  FIG. 5 , when the inner doors  104  and the outer doors  105  are deployed they form, overall, a continuity. 
     The stowed position of the outer doors  105  can be adopted when the frame  207   b  is in advanced position or in retracted position. The deployed position can be adopted only when the frame  207   b  is in retracted position. The deployed, respectively stowed, position of the outer doors  105  is synchronized with the deployed, respectively stowed, position of the inner doors  104 . 
     In the stowed position, each outer door  105  blocks a zone of the openwork part of the frame  207   b  when the latter is in advanced position and the same zone of the openwork part of the frame  207   b  and a zone of the window  210  when the frame  207   b  is in a retracted position. In the deployed position, the outer door  105  does not block the zone of the window  210  or the openwork part of the frame  207   b  and extends towards the outside of the nacelle  102  allowing the passage of the secondary flow  208 . 
     Thus, in the stowed position, each outer door  105  is overall in the extension of the mobile cowl  207   a  and in the deployed position, each outer door  105  is opened outwards and deflects the part of the secondary flow  208  which has previously been deflected by the inner doors  104  through the window  210 . 
     In the stowed position, the outer doors  105  are arranged between the mobile cowl  207   a  and the fixed structure  206  so as to form an outer wall of the nacelle  102  which is therefore in contact with the air flow which flows around the nacelle  102 . 
     In the advanced position, each outer door  105  is positioned outside of the inner doors  104 . 
     Each outer door  105  is articulated by a downstream edge, relative to the direction of flow, at the downstream part of the frame  207   b  on hinges  212  fixed to the frame  207   b  whereas the opposite free edge is positioned towards the upstream direction in the stowed position and towards the outside in the deployed position. 
     In the embodiment of the invention presented in  FIGS. 3 to 5 , the hinges  212  of the inner doors  104  and of the outer doors  105  are merged, but they could be staggered. 
     For each pair of doors  104 ,  105 , the thrust reversing system  250  has a runner  214  associated with the pair of doors  104 ,  105 . The runner  214  is mounted to be translationally mobile in a direction parallel to the direction of translation on the frame  207   b . The runner  214  is thus mobile between a first position and a second position. 
     The switching from the stowed position to the deployed position of each door  104 ,  105  of the pair is mechanically associated with the switching of the runner  214  from the first position to the second position and vice versa. 
     In the particular embodiment presented here, the thrust reversing system  250  also has, for each runner  214 , a first transmission system  216  which, for the inner door  104  associated with the runner  214 , here takes the form of a rod articulated by one end to the inner door  104  and articulated by another end to the runner  214 . 
     In the same way, the thrust reversing system  250  also has, for the runner  214 , a second transmission system  217  which, for the outer door  105  associated with the runner  214 , here takes the form of a rod articulated by one end to the outer door  105  and articulated by another end to the runner  214 . 
     The first transmission system  216  is provided to switch the inner door  104  associated with the runner  214  from the stowed position to the deployed position simultaneously with the switching of the runner  214  from the first position to the second position in order to open the inner door  104  and vice versa. 
     The second transmission system  217  is provided to switch the outer door  105  associated with the runner  214  from the stowed position to the deployed position simultaneously with the switching of the runner  214  from the first position to the second position in order to open the outer door  105  and vice versa. 
     In the embodiment of the invention presented here, the first position comprises displacing the runner  214  forwards whereas the second position comprises displacing the runner  214  backwards. 
     The translation of the runner  214  is produced by guide systems between the frame  207   b  and the runner  214  which can, for example, take the same form of a rail  215  of the frame  207   b.    
     The switching from the advanced position of the frame  207   b  to the retracted position of the frame  207   b  and the deployed position of the inner doors  104  and of the outer doors  105  comprises therefore, from the advanced position of the frame  207   b  and therefore from the stowed positions of the inner  104  and outer  105  doors, retracting the frame  207   b  by translation relative to front frame  206  to reach the retracted position for the frame  207   b  and the stowed positions of the inner  104  and outer  105  doors, then in displacing each runner  214  from the first position to the second position to switch the inner doors  104  and the outer doors  105  from the stowed position to the deployed position. 
     The reverse displacement makes it possible to revert to the advanced position. 
     The nacelle  102  also comprises a set of actuators  218  and  220  ensuring the translational displacement of the frame  207   b  and of the runner  214 . Each actuator  218 ,  220  is controlled by a control unit, for example of the processor type, which controls the displacements in one direction or the other depending on the needs of the aircraft  10 . 
     Each actuator  218 ,  220  can for example take the form of an electric ball jack or any other appropriate types of jacks. 
     To ensure the displacement of the frame  207   b , the nacelle  102  comprises at least one first actuator  218  of which there are three here, and which are fixed between the fixed structure  206  of the nacelle  102 , and the frame  207   b . Each first actuator  218  is thus provided to ensure, from the advanced position of the frame  207   b  and therefore from the stowed positions of the inner  104  and outer  105  doors, a translational displacement of the frame  207   b  to the retracted position, and vice versa. During the displacement of the frame  207   b , each runner  214  which is borne by the frame  207   b  follows the same displacement. 
     To ensure the displacement of each runner  214 , and therefore of each inner  104  and outer  105  door, the thrust reversing system  250  comprises, for each runner  214 , a second actuator  220  which is fixed between the frame  207   b  and the runner  214 . The second actuator  220  is provided to ensure the translational displacement of the runner  214  from the first position to the second position. 
     The second actuator  220  is distinct from each first actuator  218  and they can therefore be displaced independently of one another. The displacement of the mobile assembly  207  from the advanced position to the retracted position is disassociated from the displacement of the doors  104  and  105 . 
       FIG. 7  shows a functional diagram of a displacement method  700  for the thrust reversing system  250  which comprises, from the advanced position of the mobile assembly  207 , from the stowed positions of the inner  104  and outer  105  doors, from the first position of the runners  214 :
         a first activation step  702  during which each first actuator  218  is activated to ensure the translational displacement of the mobile assembly  207  and therefore of the frame  207   b  from the advanced position to the retracted position, then   a second activation step  704  during which each second actuator  220  is activated to ensure the translational displacement of the associated runner  214  from the first position to the second position, then   a third activation step  706  during which each second actuator  220  is activated to ensure the translational displacement of the associated runner  214  from the second position to the first position, then   a fourth activation step  708  during which each first actuator  218  is activated to ensure the translational displacement of the mobile assembly  207  and therefore of the frame  207   b  from the retracted position to the advanced position.       

     The invention has been more particularly described in the case of a nacelle under a wing but it can be applied to a nacelle situated at the rear of the fuselage. 
     In order to better control the secondary flow  208 , the nacelle  102  comprises at least one baffle plate  226  (if there are several thereof, it is then a cascade-type gate) which is arranged around the secondary jet  202  at the entry of the window  210 , that is to say, overall, at the zone of transition from the secondary jet  202  to the window  210  in a zone where the flow has the greatest difficulty in turning to create reverse thrust (that is to say forward of the nacelle). 
     Each baffle plate  226  is fixed to the fixed structure  206  of the nacelle  102 , and it is fixed here for example to the fan casing  206   a . Each baffle plate  226  takes the form of an aileron which orients the secondary flow  208  towards the window  210  then towards the front of the dual flow jet engine  100 . In the embodiment of the invention presented here, the mobile cowl  207   a  comprises an inner wall oriented towards the secondary jet  202  and an outer wall oriented towards the outside of the nacelle  102 , and in position of closure, each baffle plate  226  is housed in the mobile assembly  207 , that is to say, between the inner wall and the outer wall. 
     While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.