Abstract:
A drive mechanism for deforming a skin of a deformable structural component of a fluid-dynamic flow body to provide a space-saving drive concept for large deformations under great loads. The drive mechanism comprises a linearly movably driven linear movement unit, and a transmission element configured to translate linear movement of the linear movement unit into rotary movement of a rotatably mounted load introduction device of the structural component to introduce a deformation force onto the skin.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. §119(a) to European Patent Application No. 13 196 994.1, filed on Dec. 12, 2013, the entire contents of European Patent Application No. 13 196 994.1 are hereby incorporated herein by reference. 
     BACKGROUND 
     Field of the Invention 
     The invention relates to a drive mechanism for driving a deformation of a skin of a deformable structural component of a fluid-dynamic, in particular aerodynamic, flow body, which structural component has a skin to be deformed and a rotatably mounted load introduction device for introducing the deformation force onto the skin. Further, the invention relates to a deformable structural component for a fluid-dynamic, in particular aerodynamic, body of a vehicle, in particular an aircraft, comprising a skin to be deformed and such a drive mechanism. Further, the invention relates to a vehicle&#39;s fluid-dynamic, in particular aerodynamic, flow body, such as a wing or the like of an aircraft, provided with such a deformable structural component. Finally, the invention relates to a lift-assisting device for an airplane. 
     Background Information 
     A deformable structural component with a drive mechanism for driving the deformation has been developed and investigated, for example, in the research project “SmartLED” (LuFo4) and in the research project “SADE(EU)”. Further details regarding the project “SADE” and a documentation of publications pertaining thereto are available on the website www.sade-projekt.eu/index.html. 
     Adaptive structures of the type investigated in the SADE project are particularly suitable for deforming aerodynamic surfaces of aircraft, such as wings, fins or rotor blades, for example. In particular in the case of airplane wings, it is advantageous to use so-called droop leading edge flaps (or droop noses) as lift-assisting devices, instead of conventional slats. In the case of the droop nose, which is hereinafter referred to by this term, the entire wing nose is angled in a downward direction. The wing camber thus increases. One implementation of a droop nose is realized, as a so-called droop nose device, on the inner wing of the Airbus A380, for example. 
     SUMMARY 
     Conventional slats are unsuitable for laminar flows and, further, are a dominant source of noise. In the case of the Airbus A380, however, a droop nose device is realized through a rigid body movement, which already provides major advantages over conventional slats. 
     The investigations of the SADE project have the aim of obtaining adaptive structures for aerodynamic bodies with which greater geometric liberties, a reduction of local bending and loads and more laminar flows can be obtained as compared with known droop nose devices. 
     In the case of earlier droop nose solutions, the entire front nose of the wing as a whole is moved as a rigid body. However, the SADE project is based on the approach of deforming the primary structure. Thus, it is possible to work without any gaps with a closed aerodynamic surface, avoid large local radii of curvature and therefore also achieve an improved cp distribution and a lower separation tendency. 
     Therefore, a disclosed embodiment is directed to a drive concept for a deformable structural component with a skin to be deformed over a large area, which structural component can be deformed by a drive mechanism in order to create an adaptive structure. 
     In the case of previous deformable, adaptive, thin-walled structures, such as for a droop nose, for example, the introduction of forces preferably takes place by means of an auxiliary structure (e.g. an omega stringer) in order to reduce local excessive tensions and to not interfere with the deformability of the primary structure. Fittings are attached to this auxiliary structure in order to enable through them a movably mounted force introduction (e.g. via struts and joint head). In previous solutions, the struts are each situated on a main lever, with each main lever being provided with an actuating motor for rotating the main lever. 
     If, however, the creation of a wing or other fluid-dynamic body for a vehicle, such as particularly an aerodynamic body for an aircraft, is desired, which can be surrounded by a laminar flow, then as slim a structure as possible—e.g. a slim laminar-flow wing—would be advantageous. In particularly slim laminar-flow wings, the previous solutions cannot be employed with the given geometry, due to lack of space; the functional capability of the required kinematic mechanism would not be provided in this case. 
     Certain disclosed embodiments provide a drive concept for a kinematic mechanism of an adaptive structure with a small space requirement for a large deformation at large loads with a reduced complexity of the drive. 
     One embodiment provides a drive mechanism for driving a deformation of a skin of a deformable structural component of a fluid-dynamic, in particular aerodynamic, flow body, which structural component has a skin to be deformed and a rotatably mounted load introduction device for introducing the deformation force onto the skin, wherein the drive mechanism comprises a linearly movably driven linear movement unit and a transmission element for translating a linear movement of the linear movement unit into a rotary movement of the load introduction device. 
     According to a disclosed embodiment, the transmission element has a translation lever for translating the linear movement into a rotary movement. The translation lever acts on the linear movement unit and on the load introducing device. The translation lever is configured as a toggle joint or as a part of a toggle joint mechanism. Also, the translation lever is mounted in an articulated manner in such a way that it is able to move both in a single plane as well as move out of the plane. 
     According to a disclosed embodiment, the translation lever is mounted on the linear movement unit in a multi-axially articulated manner. The translation lever can be mounted on the load introduction device in a multi-axially articulated manner. The translation lever can be mounted on the linear movement unit in a mono-axially articulated manner and the linear movement element is mounted rotatably about a torsion axis substantially extending in the direction of movement of the linear movement element. 
     According to a disclosed embodiment, the linear movement unit is configured and arranged in such a way that the direction of movement of the linear movement unit extends parallel to an axis of rotation of the rotary movement of the load introducing device with at least one movement direction component, preferably with its largest movement direction component, or in its entirety. The linear movement unit has a drive rod displaceably mounted in its longitudinal direction. The linear movement unit has several rod elements successively arranged in the direction of movement and coupled to each other in an articulated manner. 
     Another disclosed embodiment provides a deformable structural component, provided with such a drive mechanism, for a fluid-dynamic body of a vehicle—in particular for an aerodynamic body of an aircraft—comprising a skin to be deformed and the drive mechanism for driving the deforming movement. The skin is fixed at its end portions so as to be stationary and the drive mechanism is configured to deform a middle portion of the skin that extends in a curved manner between the end portions. 
     A further embodiment provides a fluid-dynamic, in particular aerodynamic, flow body, which is provided with such a deformable structural component driven by the drive mechanism, and in which a trailing edge region is formed by the deformable structural component. 
     Still another embodiment provides a lift-assisting device for an airplane, which is formed with such a structural component that can be deformed driven by the drive mechanism, and which is configured as a droop nose device. 
     Thus, disclosed embodiments configure a leading edge of a laminar-flow profile (such as a leading wing edge of a laminar-flow wing) in an adaptively deformable manner. This requires a drive concept or kinematic mechanism. However, especially in the case of laminar-flow profiles, there is a lack of construction space which allows only for a limited number of actuators. In addition, the loads to be coped with are very large. A classic rotary driven kinematic mechanism is not feasible in very slim laminar-flow profiles to be deformed. In particular, in the case of the preferred applicability as a droop nose lift-assisting device, a large load arises at the leading edges of wings of aircraft, with only little available construction space. 
     Another aim of the disclosed embodiments is to provide a solution for reducing the complexity. Previous rotary kinematic mechanisms investigated in the SADE projection cannot be used in the case of very slim laminar-flow profiles with little construction space, even if, in their intended use, they offer a similar solution—the deformation of a leading wing edge. The solution contemplated so far is significantly more complex and geometrically less flexible than the drive concept presented herein. 
     According to a disclose embodiment, a linear link to the kinematic mechanism is proposed as a drive concept, in which the linear movement is translated into a rotary movement by a specific positioning of levers. To this end, a lever is mounted in an articulated manner in such a way that it is able to move both in the plane as well as out of it. 
     Generally, construction space can be gained and the complexity can be greatly reduced by the concept according to the disclosed embodiments. Other advantages are a possible reduction of weight, high stability and a greater fail-safeness. In addition, any number of kinematic mechanism stations can basically be driven at the same time due to the drive concept. Thus, the complexity of the system is greatly reduced. Another advantage is that, in the case of minimum or maximum kinematic mechanism amplitude, the actuator(s) can be free from load, whereby the safety of the system is increased. 
     As in the case of previous deformable, adaptive, thin-walled structures, such as for a droop nose, for example, the introduction of forces, also in preferred applications of the invention, preferably takes place by means of an auxiliary structure (e.g. an omega stringer) in order to reduce local excessive tensions and to not interfere with the deformability of the primary structure. Preferably, fittings are attached to this auxiliary structure in order to enable through them a movably mounted force introduction (e.g. via struts and joint head). Preferably, the struts are respectively situated on one of several main levers. With the drive concept according to the invention, however, the main levers can be driven much in a much simpler and safer manner than was the case so far. A linear movement of a linear movement unit can easily be transmitted along a wing edge or other elongate structure to be deformed, and be tapped at several locations, in order also to drive several main levers in this manner. The linear movement can be translated into a rotary movement of the respective main lever elegantly and simply, and nevertheless safely and also with high loads, and also so as to require little maintenance, by means of a translation lever, with the weight requirements also being small. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the invention will be explained in more detail below with reference to the attached drawings. In the drawings: 
         FIG. 1  shows a schematic top view onto an aircraft in the form of an airplane with a droop nose lift-assisting device for illustrating an example for adaptive structures with a deformable structural component and a drive mechanism for driving a deformation; 
         FIG. 2  shows a section along the line II-II of  FIG. 1  through the adaptive structure and the deformable structural component; 
         FIG. 3  shows a perspective view of an embodiment of the drive mechanism in a neutral position; 
         FIG. 4  shows a view as in  FIG. 3  of the drive mechanism in a position for maximum deformation; 
         FIG. 5  shows another view of the drive mechanism, with an attachment fitting for a load introducing device having been omitted for better illustration; 
         FIG. 6  shows an illustration comparable with  FIG. 5  with both attachment fittings, and 
         FIG. 7  shows another drive mechanism. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     With reference to the illustrations of  FIGS. 1 and 2 , an exemplary embodiment of an adaptive thin-walled structure  10  with a deformable structural component  12  will be explained in more detail below, taking a fluid-dynamic flow body—in this case in the form of, for example, an aerodynamic flow body  14  with a deformable aerodynamic surface—as an example. However, the invention can generally be applied to all thin-walled adaptive structures with deformable structural components that have a skin  16  to be deformed and an (e.g. indirect) load introduction, e.g. via stiffening profiles  18 , for deforming the skin  16 . In particular, a drive mechanism  11  for the adaptive structure  10  will be explained in detail below. 
     Then, an exemplary embodiment of the drive mechanism  11  will be explained in more detail with reference to the illustration of  FIGS. 3 to 7 . 
       FIG. 1  shows, as an example for the fluid-dynamic, and in particular aerodynamic, flow body  14 , an aircraft  20 , in this case e.g. in the form of an airplane  22 , with the wings  24  being provided with droop nose lift-assisting devices  26 , which are realized by the adaptive structure  10 . 
     A cross-sectional illustration along the line II-II of  FIG. 1  is depicted in  FIG. 2 . According thereto, the adaptive structure  10  comprises the deformable structural component  12 . The deformable structural component  12  is configured as a part of the aerodynamic flow body  14  and comprises the skin  16 , which is to be deformed as a whole over a large surface area in order to adapt the aerodynamic flow body  14  to a desired aerodynamic effect. 
     Accordingly, the adaptive structure  10  has a deformable primary structure  28 , which is to be deformed so as to be as undisturbed as possible, wherein no gaps and no excessive radii of curvature are to be produced on the top side. For this purpose, the deformation force is introduced only indirectly into the primary structure  28  via an auxiliary structure  30 . 
     The auxiliary structure  30  has several stiffening profiles  18 . For example, the stiffening profiles  18  are formed by omega stringers  32 . Other stiffening profile shapes are also possible; however, hollow profiles with an attachment to the skin  16  distributed over a larger surface area are preferred. Accordingly, the stiffening profiles  18  are attached to an inner surface  34  of the skin  16  to be deformed. 
     The drive mechanism  11  comprises at least one actuator  36  for generating a desired deformation force. In order to introduce the deformation load, the drive mechanism  11  is connected to the stiffening profiles  18  via a load introduction device  38 . The load introduction device  38  comprises load introduction elements  40  that introduce the load at points of application  42 —also referred to as points of action—into the stiffening profiles  18  or, more generally, into the auxiliary structure  30 . 
     As shown in the  FIG. 1 , the actuator  36  is configured to produce a linear movement. For example, the actuator  36  comprises an actuating motor  44 , which drives a linear movement on the drive mechanism  11  via a motor-driven spindle (not shown). In other embodiments, a hydraulic or pneumatic or magnetic or otherwise configured piston mechanism is provided as an actuator  36 . Linear motors or an actuating motor with a toothed rack, etc., are also conceivable. 
     The drive mechanism  11  drives a rotary movement on the load introduction device  38 , by means of which a force is introduced via struts  48  with a joint head  50  into load introduction elements  40  configured as fittings  52  at the point of application  42 . The drive mechanism  11  is configured for driving the deformation of the skin  16  of the deformable structural component  12  of the aerodynamic flow body  14 . The structural component  12  comprises the skin  16  to be deformed and the rotatably mounted load introduction device  38  for introducing the deformation force onto the skin  16 . 
     As is apparent from  FIG. 2 , the drive mechanism  11  moreover has a linear movement unit  60  that is driven in a linearly movable manner by the actuator  36  and a transmission element  62  for translating a linear movement of the linear movement unit  60  into a rotary movement of the load introduction device  38 . The transmission element  62  is formed, in particular, by a translation lever  64  that, on the one hand, is hinged to the linear movement unit  60  and, on the other hand, to the load introducing device  38 . 
     For this purpose, the load introducing device  38  has a main lever  54 , which has a two-arm configuration, wherein the translation lever  64 , which acts as a transmission element  62  for translating the linear movement into a rotary movement, is hinged to a first arm  66 , and the struts  48  with the joint heads  50  act on a second arm  68 . The first arm  66  and the translation lever  64  form a toggle joint mechanism, with which even large loads can be transmitted. 
     The stiffening profiles  18  are each formed by an omega stringer  32  extending in the longitudinal direction of the structural component  12  to be deformed. In the exemplary use of the adaptive structure  10  shown in  FIG. 1 , the longitudinal direction corresponds to the direction of the wing span. At several spaced-apart locations, there are fittings  52  of which only one, respectively, is shown. 
     The direction of linear movement  68  of the linear movement unit  60  extends parallel to this longitudinal direction and with at least one directional component also parallel to the axis of rotation of the rotary movement of the load introducing device, i.e. in particular of the individual main levers  54 . In the illustrated embodiment of a wing edge to be deformed, the direction of linear movement is directed substantially parallel to the direction of the wing edge, i.e. substantially in the direction of the wing span. The main lever  54  is directed substantially in the direction of flight, with its axis of rotation extending substantially parallel to the direction of linear movement  58 . 
     As shown in  FIG. 2 , the load introduction device  38  has as the load introduction element  40  the main lever  54  and struts  48  with a joint head  50 , which are hinged to the free end thereof, for connection with the fitting  52  in the omega stringers  32 . The skin  16  is fixed in a stationary manner at the end portions or transition portions  70 , where the deformable structure  10  transitions into a rigid structure of the aerodynamic flow body  14 . For example, the skin  16  is attached to a wall  72  of the wing structure at these transition portions  70 . The skin is curved in an arcuate manner from the lower transition portion to the upper transition portion in order to form the leading wing edge  74 . The entire curved portion of the skin  16  can be deformed as a whole. The load introduction device  38  moreover has an attachment fitting  76 , which is also attached in a stationary manner, e.g. to the wall  72  of the wing structure. The axis of rotation  78  of the rotary movement  80  of the load introduction device  38  is defined at this attachment fitting  76 . 
     In the following, an exemplary embodiment of the drive mechanism will be explained in more detail with reference to the illustrations of  FIGS. 3 to 7 . 
     The linear movement unit  60  of the drive mechanism  11  has a drive rod  82  which has at one end thereof an actuator connector  84  for coupling it to an output member of the actuator  86 . The drive rod  82  is mounted in guide rails  86 , which may be disposed on the attachment fitting  76 , so as to be linearly displaceable in the direction of linear movement  58 . 
     The drive rod  82  is preferably divided into several rod elements  87 ,  88  which are coupled to each other in an articulated manner by means of a coupling joint  89 , in order to compensate for the bending of the aerodynamic flow body  14 , in particular for the bending of the wing  24 . As can best be seen from  FIG. 7 , the drive rod  82  can thus be guided to several main levers  54  and thus drive several main levers  54  together. 
     In the area of the attachment fittings  76  of each main lever, the drive rod  82  has a joint connector  90  for the articulated, i.e. e.g. rotatable, hinge mounting of a first end of the translation lever  64 . In one embodiment, the joint between the translation lever  64  and the drive rod  82  formed by the joint connector  90  is a multi-axis joint, in order, on the one hand, to enable a rotation of the translation lever  64  in a plane orientated in the direction of linear movement  58  and in the vertical direction, and, moreover, to enable a forward pivoting movement of the translation lever  64 , i.e. towards the skin to be deformed, in order thus to compensate for the movement of the first arm  66  of the main lever  54 . To this end, the joint connector  90  can be, for example, a part of a cross joint or of a ball joint. The second end of the translation lever  64  is hinged to the first arm  66  with a corresponding joint with several degrees of freedom. 
     In another embodiment, which is not shown here in more detail, the joint at the joint connector  90  is a pure hinge joint with only a single degree of freedom, and the drive rod  82  is rotatably mounted about its longitudinal axis.