Patent Publication Number: US-2022219808-A1

Title: Actuator arrangement for a fixed leading edge member of an aircraft, wing assembly and aircraft equipped with said actuator arrangement

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of the International Application No. PCT/EP2020/075643, filed on Sep. 14, 2020, and of the German patent application No. 102019124987.2 filed on Sep. 17, 2019, the entire disclosures of which are incorporated herein by way of reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to an actuator arrangement for a fixed leading edge member of an aircraft. Furthermore, the invention relates to a wing assembly and an aircraft equipped with such an actuator arrangement. 
     BACKGROUND OF THE INVENTION 
     Most known slat actuation architectures have a static geared rotary actuator (GRA) that drives the slat via a pinon. For some applications, like, e.g., droop nose or for space allocation (e.g., short curved track principle) lever bearing assemblies are preferred. 
     U.S. Pat. No. 4,979,700 A discloses a typical GRA for a leading edge of an aircraft. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to improve an actuator arrangement for high-lift devices. 
     The invention provides an actuator arrangement for a fixed leading edge member, the fixed leading edge member having an inner cavity at least in part defined by an outer skin and a rib, the actuator arrangement being configured for extending and retracting at least one high-lift device attached to the fixed leading edge member, the actuator arrangement comprising:
         a fixed leading edge lever configured for being attached to the fixed leading edge member,   a high-lift device lever configured for being attached to the high-lift device, and   an actuator assembly that is configured for driving the fixed leading edge lever and the high-lift device lever relative to each other, the actuator assembly including at least one actuator, preferably a geared rotary actuator, wherein the actuator assembly is configured such that, when the fixed leading edge lever and the high-lift device lever are attached to the high-lift device and the fixed leading edge member, respectively, the actuator is movable during extending and retracting of the high-lift device between a fully retracted position, in which the actuator is predominantly accommodated within the inner cavity, and a fully extended position, in which the actuator is predominantly positioned outside the inner cavity.       

     Preferably, the actuator is movable along a circular arc section in a forward direction during extending of the high-lift device and/or in an aft direction during retracting of the high-lift device. 
     Preferably, the actuator is rotatable about a rotational axis that is defined by the mounting point of the fixed leading edge lever. 
     Preferably, the actuator, when in the fully retracted position, is wholly accommodated within the inner cavity. 
     Preferably, the actuator, when in the fully extended position, is wholly positioned outside the inner cavity. 
     Preferably, the actuator assembly includes at least two actuators and two actuators each are grouped together into a respective actuator group for driving one high-lift device. 
     Preferably, the actuator arrangement further comprises a drive unit providing mechanical power for driving the actuator assembly 
     Preferably, the actuator assembly includes a spanwise drive train having at least one spanwise straight drive shaft, which mechanically couples two adjacent actuators. 
     Preferably, the actuator assembly includes a first actuator and a second actuator, wherein the first actuator is mechanically coupled to the drive unit. 
     Preferably, the first actuator is mechanically coupled to the drive unit via a pivotable drive shaft. 
     Preferably, the second actuator is mechanically coupled to the first actuator via a spanwise straight drive shaft. 
     Preferably, the drive unit is arranged spanwise between adjacent actuators associated with one high-lift device 
     Preferably, the drive unit is arranged on the same axis as the actuator in a spanwise direction. 
     Preferably, the drive unit is arranged aft of the actuator. 
     Preferably, the drive unit is arranged below the actuator. 
     Preferably, the drive unit is arranged aft and below of the actuator. 
     Preferably, the drive unit is arranged adjacent to the actuator in a spanwise direction or chordwise direction. 
     Preferably, the drive unit is configured to be arranged predominantly, in particular entirely, within an upper half of the inner cavity in the fully retracted position. 
     Preferably, the drive unit is configured to be arranged partially, in particular predominantly, within a lower half of the inner cavity in the fully extended position. 
     Preferably, the drive unit is configured to be arranged within the inner cavity, when in the fully retracted position, in the fully extended position and when moving between said positions. 
     Preferably, the drive unit is configured to be arranged predominantly, in particular entirely, within a lower half of the inner cavity in the fully retracted position. 
     Preferably, the drive unit is configured to be arranged partially outside inner cavity in the fully extended position. 
     Preferably, the drive unit is configured to be arranged to protrude downward through a cut-out of the fixed leading edge member. 
     Preferably, the drive unit is attached to the actuator assembly, so as to be simultaneously movable. 
     Preferably, the drive unit has at least one motor for driving the actuator. 
     Preferably, the drive unit has at least one electric motor for driving the actuator. 
     Preferably, the drive unit has at least one hydraulic motor for driving the actuator. 
     Preferably, one or each motor is mechanically coupled to two adjacent actuators associated with one high-lift device, in particular via a spanwise straight drive shaft. 
     Preferably, one or each motor is arranged aft of and adjacent to the actuator when viewed in a top view. 
     Preferably, one or each motor is arranged aft of and below the actuator and adjacent to the actuator when viewed in a top view. 
     Preferably, one or each motor is arranged on the same axis as the actuator in a spanwise direction. 
     The invention provides a wing assembly for an aircraft, the wing assembly comprising a fixed leading edge member, a high-lift device movably attached to the fixed leading edge member, and a preferred actuator arrangement, wherein the fixed leading edge lever is attached to the fixed leading edge and the high-lift device lever is attached to the high-lift device, so as to allow movement of the high-lift device between a retraced position and a fully extended position. 
     The invention provides an aircraft comprising a preferred wing assembly. 
     The preferred configurations allow for a GRA to be integrated into the lever architecture. The stroke of the GRA may be maximized using the preferred configurations, thereby increasing efficiency. This may be achieved due to a reduction of the required forces by increasing travel, thus reducing actuation momentum. As a result, gear sizes within the GRA and the overall size of the GRA may be reduced. Consequently, weight and space efficiency are improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the invention are described in more detail with reference to the accompanying schematic drawings: 
         FIG. 1  depicts an embodiment of an aircraft; 
         FIG. 2  depicts an embodiment of an actuator arrangement; 
         FIG. 3  depicts a cross-section of the actuator arrangement of  FIG. 2  in the fully retracted and extended positions; 
         FIG. 4  depicts a cross-section of the actuator arrangement of  FIG. 2  in the fully retracted position; 
         FIG. 5  depicts a cross-section of the actuator arrangement of  FIG. 2  in the fully extended position; 
         FIG. 6  depicts a cross-section of another embodiment of an actuator arrangement in the fully retracted and extended positions; 
         FIG. 7  depicts a top view of the actuator arrangement of  FIG. 6  in the fully retracted (upper) and extended positions (lower); 
         FIG. 8  depicts a cross-section of another embodiment of an actuator arrangement in the fully retracted and extended positions; 
         FIG. 9  depicts a top view of the actuator arrangement of  FIG. 8  in the fully retracted position; 
         FIG. 10  depicts a variant of the actuator arrangement of  FIG. 8 ; 
         FIG. 11  depicts a cross-section of another embodiment of an actuator arrangement in the fully retracted and extended positions; 
         FIG. 12  depicts a variant of the actuator arrangement of  FIG. 11 ; and 
         FIG. 13  depicts a top view of the actuator arrangement of  FIG. 12  in the fully retracted position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , an embodiment of an aircraft  10  is depicted. In a known manner, the aircraft  10  comprises a fuselage  12 , a vertical tail plane  14  and a horizontal tail plane  16 . Furthermore, the aircraft  10  comprises a wing assembly  18 , which comprises at least one high-lift device  20 , such as a slat  22 . 
     Referring now to  FIGS. 2 to 5 , an actuator arrangement  24  is configured to move the high-lift device  20  between a fully retracted position ( FIG. 4 ) and a fully extended position ( FIG. 5 ). 
     As depicted more closely in  FIG. 2 , the high-lift device  20  is movably attached to a fixed leading edge member  26  ( FIG. 3 ) using a plurality of rails  28 , which are supported by roller bearings  30 . The rails  28  are attached to the high-lift device  20  via a lever assembly  32 . 
     In the present embodiment, the actuator arrangement  24  comprises two fixed leading edge levers  34 . The fixed leading edge lever  34  is mechanically coupled to the fixed leading edge member  26 . 
     Furthermore, the actuator arrangement  24  comprises a high-lift device lever  36 . The high-lift device lever  36  is coupled to the high-lift device  20 . 
     Furthermore, the actuator arrangement  24  comprises an actuator assembly  38 . The actuator assembly  38  is configured for driving the fixed leading edge lever  34  and the high-lift device lever  36  relative to each other, so as to extend and retract the high-lift device  20 . 
     The actuator assembly  38  comprises at least one actuator  40 . The actuator  40  is preferably a geared rotary actuator  42 . 
     The fixed leading edge member  26  comprises, in manner known per se, an outer skin  44  and a plurality of ribs  46 , which support the outer skin  44 . Adjacent ribs  46  and the outer skin  44  define an inner cavity  48  of the fixed leading edge member  26 . 
     Furthermore, the outer skin  44  comprises so-called D-nose cut-outs  50 , which allow extending and retracting the high-lift device  20  via the actuator arrangement  24  and the rails  28 . 
     In this embodiment, the actuator  40  is arranged predominately inside the inner cavity  48 , when in the fully retracted position ( FIG. 4 ). Furthermore, the actuator  40  is arranged predominately in an upper half of the inner cavity  48 , when in the fully retracted position. 
     In order to extend the high-lift device  20  the actuator arrangement  24  is operated. In doing so, the actuator  40  moves the fixed leading edge lever  34  relative to the high-lift device lever  36 . 
     As indicated in  FIGS. 4 and 5 , the fixed leading edge lever  34  and the high-lift device lever  36  stretch in the forward aft direction. In other words, the angle between the fixed leading edge lever  34  and the high-lift device lever  36  is acute at the beginning and increases to be more than 90 degrees in the extended position ( FIG. 5 ). During the movement of the high-lift device  20 , the actuator  40  itself follows the movement along a circular arc section  52  until the actuator  40  is arranged entirely outside the inner cavity  48 , when in the fully extended position. Thus, the actuator  40  preferably rotates about a rotational axis  53 . The rotational axis  53  is defined by the mounting point of the fixed leading edge lever  34 . 
     It should be noted that in the following further embodiments are only described in so far as they differ from the embodiment described above. 
     Referring to  FIGS. 6 and 7  the actuator arrangement  24  comprises a plurality of actuators  40 . Each actuator  40  has an input shaft  54  and an output shaft  56 . 
     Furthermore, the actuator arrangement  24  comprises a drive unit  58 . The drive unit  58  may be hydraulic or electric in nature. 
     The actuator arrangement  24  comprises a drive train formed by a plurality of straight drive shafts  62 , which are aligned substantially along the spanwise direction. 
     The drive unit  58  may be fixed in place and be connected to a first actuator  64  using an initial drive shaft  66  and universal joints  68 . Splines  70  may be used to transfer the torque. 
     Furthermore, the actuator assembly  38  comprises a second actuator  72  which is associated with the same high-lift device  20  as the first actuator  64 . The first actuator  64  and the second actuator  72  thereby form an actuator group  74 , which is associated with the same high-lift device  20 . 
     In this embodiment a connecting drive shaft  76  is mechanically coupled to the output shaft  56  of the first actuator  64  and to the input shaft  54  of the second actuator  72 . 
     In the case of a plurality of high-lift devices  20 , the output shaft  56  of the second actuator  72  is connected to a further actuator group  78  via a further drive shaft  80 . As can be seen from  FIG. 7 , this pattern is repeated until all high-lift devices  20  and their respective actuator group  74  are mechanically connected to the drive unit  58 . 
     As can be seen from  FIG. 6 , the actuator  40  is arranged in its entirety within the inner cavity  48 , when in the fully retracted position, whereas the actuator  40  predominately protrudes outside the inner cavity  48  at the bottom in the fully extended position. The actuator  40  thus extends through one of the D-nose cut-outs  50 . 
     Referring now to  FIGS. 8 and 9 , the drive unit  58  comprises an electric motor  82 . As can be seen from  FIG. 9  in particular, each electric motor  82  is arranged on the axis defined by the actuator  40 . Here, each actuator  40  has its own electric motor  82 . 
     As illustrated in  FIG. 8 , the movement of the actuator or the actuator arrangement  24  is substantially the same as the movement in the previous embodiment. 
     Referring to  FIG. 10 , a variant of the previous actuator arrangement  24  ( FIG. 8 ) is depicted. In this variant, an actuator group  74  are driven by a single electric motor  82 , which is connected to the respective actuators  40  using a drive shaft  62 . 
     Referring now to  FIG. 11 , again each actuator  40  is driven by the drive unit  58  individually. As can be seen from  FIG. 11 , in the fully retracted position, the actuator  40  is arranged in its entirety within the inner cavity  48 , as well as the drive unit  58 . 
     In particular, the actuator  40  is arranged in an upper half of the inner cavity  48 , whereas the drive unit  58  is arranged in a lower half of the inner cavity  48 , when in the fully retracted position. 
     In the fully extended position, the actuator  40  is predominately protruding outside of the fixed leading edge member  26 , whereas the drive unit  58  is still predominately accommodated within the inner cavity  48 . 
     Similarly, in the variant depicted in  FIG. 12 , both the actuator  40  and the drive unit  58  are arranged in an upper half of the inner cavity  48  in the fully retracted position, whereas in the fully extended position, the actuator  40  protrudes outside the inner cavity  48  and the drive unit  58  is entirely accommodated within the inner cavity  48 . 
     With the described configurations of the actuator arrangement  24  the actuators  40 , such as geared rotary actuators  42 , can be integrated more easily into the small space provided by fixed leading edge member  26  and the high-lift device  20 . 
     In particular, the stroke of the actuator  40  may be maximized which allows an increase in efficiency due to a reduction of required forces for moving the high-lift device  20 . Due to the lower requirements the overall size of actuators  40  may be reduced so that weight and space efficiency are improved. Furthermore, the size of the D-nose cut-out  50  may be reduced using a preferred actuator arrangement  24 . 
     In order to improve space allocation, reduce weight and increase aerodynamic performance in high-lift devices ( 20 ), an actuator arrangement ( 24 ) for a fixed leading edge member ( 26 ) is proposed. The fixed leading edge member ( 26 ) has an inner cavity ( 48 ) defined by the outer skin ( 44 ) and ribs ( 46 ). The actuator arrangement ( 24 ) comprises at least one geared rotary actuator ( 42 ) which moves relative to the other parts along a circular arc section ( 52 ) during extending and retracting of the high-lift device ( 20 ) between a fully retracted position and a fully extended position. In the fully retracted position, the actuator ( 40 ) is predominantly accommodated within the inner cavity ( 48 ) and in the extended position the actuator ( 40 ) is predominantly positioned outside the inner cavity ( 48 ), preferably protruding through a D-nose cut-out ( 50 ). 
     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. 
     LIST OF REFERENCE SIGNS 
     
         
           10  aircraft 
           12  fuselage 
           14  vertical tail plane 
           16  horizontal tail plane 
           18  wing assembly 
           20  high-lift device 
           22  slat 
           24  actuator arrangement 
           26  fixed leading edge member 
           28  rail 
           30  roller bearing 
           32  lever assembly 
           34  fixed leading edge member lever 
           36  high-lift device lever 
           38  actuator assembly 
           40  actuator 
           42  geared rotary actuator 
           44  outer skin 
           46  rib 
           48  inner cavity 
           50  D-nose cut-out 
           52  circular arc section 
           53  rotational axis 
           54  input shaft 
           56  output shaft 
           58  drive unit 
           60  drive train 
           62  drive shaft 
           64  first actuator 
           66  initial drive shaft 
           68  universal joint 
           70  spline 
           72  second actuator 
           74  actuator group 
           76  connecting shaft 
           78  further actuator group 
           80  further drive shaft 
           82  electric motor