Abstract:
The invention relates to an nacelle member ( 1 ) comprising at least one mobile cowling ( 2 ) pivotally or slidably mounted in an essentially longitudinal direction of the nacelle, capable of displacement between an expanded position and a closed position relative to a fixed structure of the nacelle member ( 1 ) through at least one pivoting or translation guiding sleeve ( 4, 7 ) that receives a guiding shaft ( 5, 6 ). An electric heating de-icing device ( 9, 13 ) is provided inside the guiding shaft or defines an interface between the guiding shaft ( 5, 6 ) and the guiding sleeve ( 4, 7 ).

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a jet engine nacelle member, in particular a thrust reverser. 
       BACKGROUND OF THE INVENTION 
       [0002]    An aircraft is propelled by a number of jet engines each housed in a nacelle which also accommodates a collection of auxiliary actuating devices which are associated with its operation and which perform various functions when the jet engine is operating or at a standstill. These auxiliary actuating devices comprise in particular a mechanical system for actuating thrust reversers. 
         [0003]    A nacelle generally has a tubular structure comprising an air inlet upstream of the jet engine, a mid-section intended to surround a fan of the jet engine, and a downstream section accommodating thrust reversal means and intended to surround the combustion chamber of the jet engine, and is generally terminated by an exhaust nozzle whose outlet is situated downstream of the jet engine. 
         [0004]    Modern nacelles are intended to accommodate a dual-flow jet engine, or turbofan, which, by means of the rotating fan blades, is capable of generating a hot airflow (also known as the primary flow) from the combustion chamber of the jet engine, and a cold airflow (secondary flow) which flows around outside the jet engine through an annular passage, also known as a duct, formed between a cowling of the jet engine and an internal wall of the nacelle. The two airflows are ejected from the jet engine via the rear end of the nacelle. 
         [0005]    The job of a thrust reverser is to improve the braking capability of an aircraft when it is landing by redirecting forward at least some of the thrust generated by the jet engine. In this phase, the reverser obstructs the cold flow duct and directs this cold flow toward the front of the nacelle, thereby generating a counter-thrust which combines with the braking of the aircraft wheels. 
         [0006]    The means employed to achieve this reorientation of the cold flow vary according to the type of reverser. However, in all cases, the structure of a reverser comprises movable cowls which can be moved, in general by means of sleeves or tracks accommodating a guide shaft, between, on the one hand, a deployed position in which they open up, within the nacelle, a passage intended for the deflected flow and, on the other hand, a stowed position in which they close off this passage. These cowls may perform a deflection function or a function of simply activating other deflection means. 
         [0007]    A thrust reverser is required to perform its function within a wide range of atmospheric conditions, particularly at very low temperatures which may reach minus 55° C. 
         [0008]    In the event of an aborted takeoff of an aircraft, for example, that is to say when the pilot has to land urgently barely after the start of takeoff, the system for actuating the thrust reversers must be able to be actuated urgently without waiting for the entire nacelle to be thermally stabilized by the heat produced by each jet engine. 
         [0009]    In these conditions, ice or frost may still be present in the sleeves or tracks used to guide the movable cowls of the thrust reversers and may retard or even block the actuation of the thrust reversers. 
         [0010]    In a general manner, the same difficulties may be faced with any type of jet engine nacelle member comprising cowls which can be pivoted or moved translationally with respect to a fixed structure of a nacelle member. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    The present invention aims to overcome these disadvantages and for that purpose consists of a jet engine nacelle member comprising at least one movable cowl which is mounted pivotably or slidably in a substantially longitudinal direction of the nacelle, between a deployed position and a closed position with respect to a fixed structure of the nacelle member, by means of at least one sleeve for guiding the pivoting or translational movement, said sleeve accommodating a guide shaft, and wherein a heating electric deicing device is arranged inside the guide shaft, or forms an interface between the guide shaft and the guide sleeve. 
         [0012]    The confined environment and the clearances between the guide sleeve and guide shaft do not allow the ice to form a thick layer. As a result, short-term heating in the vicinity of the ice region can quickly convert the ice to water so as to allow the movable cowl to move under normal operating conditions. 
         [0013]    According to one possibility, the heating electric deicing device is arranged on an interface liner, in particular made of a plastic or organic material, and mounted on an internal wall of the guide sleeve. 
         [0014]    In this context, the deicing device is preferably arranged on a surface of the interface liner that is predetermined so as to be only slightly stressed by the movement of the guide shaft in the sleeve. 
         [0015]    According to another possibility, the deicing device, arranged inside the guide shaft, is connected to electric supply means, provided on the fixed structure of the nacelle member, by means of an electrically conductive and elastically deformable element whose deformation is aimed at compensating for the movement of the guide shaft with respect to the fixed structure of the nacelle member. 
         [0016]    The deicing device may comprise a metallic or organic base. 
         [0017]    The deicing device comprises, for example, a reflective strip with the aim of concentrating the heat released by the deicing device between the guide shaft and the guide sleeve. 
         [0018]    The activation of the deicing device may be controlled as a function of a signal from a temperature or ice detector. 
         [0019]    In an advantageous manner, the activation of the deicing device is triggered automatically from the start of the thrust reversal. 
         [0020]    The nacelle member may be a thrust reverser. 
         [0021]    In that case, the activation of the deicing device may be triggered automatically from the start of the thrust reversal. 
         [0022]    The nacelle member is, for example, a cascade-type thrust reverser in which the guide sleeve is a track and the guide shaft is a runner. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    The way in which the invention is implemented will be better understood from the detailed description set forth below with reference to the appended drawing. 
           [0024]      FIG. 1  is a partial schematic view in cross section of a jet engine nacelle member according to a first embodiment of the invention. 
           [0025]      FIG. 2  is an enlarged view of a detail in  FIG. 1 . 
           [0026]      FIG. 3  is a partial view in longitudinal section in the direction of the arrow III in  FIG. 2 . 
           [0027]      FIG. 4  illustrates the structure of deicing devices equipping the above nacelle member. 
           [0028]      FIG. 5  is a further-enlarged view of a detail in  FIG. 2 . 
           [0029]      FIG. 6  represents a deicing device in  FIG. 5 . 
           [0030]      FIG. 7  is an analogous view to  FIG. 2  showing a variant embodiment of the invention. 
           [0031]      FIG. 8  represents a deicing device in  FIG. 7 . 
           [0032]      FIG. 9  is an analogous view to  FIGS. 2 and 7  showing another variant embodiment of the invention. 
           [0033]      FIG. 10  is a partial view in longitudinal section in the direction of the arrow X in  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0034]      FIG. 1  represents an example of a jet engine nacelle member according to the invention, here produced in the form of a cascade-type thrust reverser  1 . 
         [0035]    In a manner known per se and not detailed hereinafter, the thrust reverser  1  comprises, on the one hand, cascades (not shown) for deflecting a fraction of an airflow of the jet engine (not shown) and, on the other hand, two cowls  2  which can move translationally in a substantially longitudinal direction of the nacelle and which are able to switch alternately from a closed position, in which they provide the nacelle with aerodynamic continuity and cover the deflection cascades, to an open position in which they open up a passage in the nacelle and uncover the deflection cascades. 
         [0036]    Complementary blocker doors (not shown), which are activated by the sliding movement of the cowling  2 , generally make it possible to close off the duct downstream of the cascades so as to optimize the reorientation of the cold flow. 
         [0037]    As illustrated more clearly in  FIG. 2 , the movable cowls  2  are slidably mounted on carrier fittings  3  which are arranged in lower and upper portions of a fixed structure of the reverser  1 . 
         [0038]    Each carrier fitting  3  comprises a substantially cylindrical primary guide track  4  intended for accommodating a primary guide runner  5  of a cowl  2 . 
         [0039]    In parallel, each cowl  2  has a secondary guide track  7  of substantially rectangular profile that is intended to accommodate a secondary guide runner  6  of the corresponding carrier fitting  3 . 
         [0040]    As indicated more clearly in  FIGS. 3 and 4 , a heating electric deicing device  9  is arranged on a liner  8  forming an interface between each runner  5  and the corresponding guide track  4 . 
         [0041]    The interface liner  8  is made here from a material such as Teflon, and it is mounted on an internal wall of the guide track  4 . 
         [0042]    The heating electric deicing device  9  comprises a wire metallic base (see  FIG. 4 ) fixed to a reflective strip (not shown) and electrically connected at  11  to an electric supply box (not shown) on a fixed upstream structure  10  of the reverser  1 . 
         [0043]    The reflective strip makes it possible to concentrate the heat released by the deicing device  9  toward a region between the runner  5  and its guide track  4 , and thus save energy. 
         [0044]    As is apparent from  FIGS. 5 and 6 , a second deicing device  13 , which is analogous to the device  9  presented above, is arranged on an interface liner  12  mounted on an internal wall of the secondary guide track  7 . 
         [0045]    The interface liners  8  and  12  could also be integrated into the corresponding guide tracks  4  and  7 . 
         [0046]    In the embodiment illustrated in  FIGS. 7 and 8 , the carrier fitting  103  comprises a primary guide track  104  having a profile in the form of a “D” which is open in its convex portion. The interface liner  108  has an identical profile and it tightly encloses a primary guide runner  105  having a complementary profile. 
         [0047]    The regions of the track  104  which are most stressed by the runner  105  during its translational movement are the two curved legs situated one on each side of the opening of the “D”-shaped profile of the track  104 , while the planar rear surface of the track  104  is only slightly stressed, if at all, by the runner  105 . 
         [0048]    The rectilinear portion (the vertical bar of the “D”) of the profile of the liner  108  is thus likewise little stressed during the sliding movement d of the runner  105 . The heating electric deicing device  109  is therefore placed on this planar surface of the liner  108  that is little subject to wear (see  FIG. 8 ). This planar surface is sufficiently large to ensure sufficient heating and, through its shape, it makes it easier to place the deicing device  109  on the liner  108 . 
         [0049]      FIGS. 9 and 10  illustrate another variant embodiment of the invention, in which a heating electric deicing device  209  is directly integrated into a primary guide runner  205  of the cowl. 
         [0050]    It should be noted that  FIG. 10  is a schematic view in which, for the sake of greater clarity, the track  204  has not been represented. 
         [0051]    The deicing device  209  is arranged on a tubular inner wall of the guide runner  205 . As above, the deicing device  209  is electrically connected, at  211 , to an electric supply box (not shown) on a fixed upstream structure  210  of the reverser  1 . 
         [0052]    However, this electrical connection is in this case produced via an elastically deformable electrically conducting element  214  which is designed to provide electrical continuity between the deicing device  209 , which is now translationally movable since it is combined with the guide runner  205 , and the electrical supply circuit  211  arranged fixedly on the fixed upstream structure  210  of the reverser  1 . 
         [0053]    The elastic deformation of the electrically conducting element  214  makes it possible to compensate for the positioning tolerances with the translationally movable deicing device  209  according to the movement. 
         [0054]    This embodiment does not require an interface liner since the deicing device  209  here provides heating for the runner  205  alone. 
         [0055]    In all the embodiments specified above, the activation of the deicing devices  9 ,  13 ,  109  or  209  may be systematic, in particular from the start of the thrust reversal, and/or controlled (via an electronic control and/or power system of the reverser) as a function of a signal from a detector (not shown) for detecting temperature or ice in the environment of the corresponding track  4 ,  7 ,  104  or  204 . 
         [0056]    Although the invention has been described using specific embodiments, it is quite obvious that it is in no way limited thereto and that it encompasses all technical equivalents of the means described and combinations thereof where these come within the scope of the invention.