Movable wing tip actuation system

Abstract

An aircraft wing (5) has: a fixed wing (7) having a tip (7 '); and a wing tip device (9) mounted in a rotatable manner on a hinge (11) located at the tip of the fixed wing. The wing tip device is rotatable about the hinge. An actuation system (20 ') rotates the wing tip device about the hinge. The actuation system has a motor (22 '), a plurality of geared mechanical actuators (24'), and an angle gearbox (29) coupled between the plurality of geared mechanical actuators and the motor. Each geared mechanical actuator is drivable by a motor and is arranged to convert a rotational motion into a different rotational motion. Each geared mechanical actuator is arranged along a hinge line of the hinge. An angle gearbox is disposed along the hinge line and between two of the plurality of geared mechanical actuators.

Description

Field of the Invention

[0001] The present invention relates to an aircraft wing having a movable wingtip device. Background Art

[0002] For example, it is known from WO2017118832 to use a movable wingtip device during flight. This document teaches an aircraft wing having a fixed wing with a wingtip device mounted movably at its tip, wherein the fixed wing has an upper surface and a lower surface, and the wingtip device has an upper surface and a lower surface, and the wingtip device is operable between two configurations: (i) a flight configuration for use during flight, in which the upper surface and the lower surface of the wingtip device are continuations of the upper surface and the lower surface of the fixed wing; and (ii) a load relief configuration for reducing the load during flight, in which the wingtip device moves relative to the fixed wing such that at least one of the upper surface and the lower surface of the wingtip device moves away from the corresponding surface of the fixed wing and the load on the wing is reduced; wherein the aircraft includes a restraint assembly that is operable between a restraint mode and a release mode, in which a restraint force is used to hold the wingtip device in the flight configuration in the restraint mode, and in which the restraint force on the wingtip device is released in the release mode such that the wingtip device can adopt the load relief configuration.

[0003] Once the restraint assembly is in the release mode, the wingtip device can be actuated completely passively to the load relief configuration. The wingtip device can move under the action of the aerodynamic force pressing the wingtip device towards the load relief configuration. The combination of the restraint assembly with the hinged wingtip device can be referred to as a "semi-aeroelastic" arrangement).

[0004] The wingtip device can be rotatably mounted on a hinge located at the tip of the wing such that it can rotate about the hinge between the flight configuration and the load relief configuration. The wingtip device is also capable of moving about the same hinge to a ground configuration for use during ground-based operations, in which the wingtip device moves away from the flight configuration such that the wingspan of the aircraft wing is reduced.

[0005] The actuation system can be arranged to move the wingtip device between the flight configuration and the ground configuration. The actuation mechanism can also be arranged to move the wingtip device back from the load relief configuration to the flight configuration.

[0006] It has been found that the actuation system may need to extend beyond the airfoil profile of the wing and the fairing of the wingtip device at the hinge, which has a negative impact on the aerodynamic drag. The fairing can extend above and / or below and / or in front of and / or behind the airfoil profile of the wing and the wingtip device. Summary of the Invention

[0007] A first aspect of the present invention provides an aircraft wing, the aircraft wing comprising: a fixed wing having a tip; a wing tip device rotatably mounted on a hinge at the tip of the fixed wing such that the wing tip device can rotate about the hinge; and an actuation system for rotating the wing tip device about the hinge, wherein the actuation system includes a motor, a plurality of gear-driven mechanical actuators, and an angle gearbox coupled between the plurality of gear-driven mechanical actuators and the motor, each gear-driven mechanical actuator being drivable by the motor and arranged to convert a rotational motion into a different rotational motion, each gear-driven mechanical actuator being arranged along the hinge line of the hinge, and wherein the angle gearbox is arranged along the hinge line and arranged between two of the plurality of gear-driven mechanical actuators.

[0008] The advantage of the present invention is that the angle gearbox enables the motor to be positioned away from the hinge line, thus releasing more space for the gear-driven mechanical actuators (GRAs) at the hinge. This can allow an increase in the number of GRAs at the hinge while achieving an overall shorter length of the actuation system at the hinge, resulting in a shorter fairing and a lower drag impact. Providing an increased number of GRAs may be beneficial because the GRAs can have a smaller diameter without reducing the torque output of the actuation system. GRAs with a smaller diameter can achieve a shallower fairing or even enable the actuation system to fit within the wing profile, thus providing a lower drag impact. Although there is additional space at the hinge, it may be difficult to drive a large number of GRAs from one end. By positioning the angle gearbox between two of the plurality of gear-driven mechanical actuators, the number of gear-driven mechanical actuators driven from one end does not increase.

[0009] The actuation system may include at least four gear-driven mechanical actuators.

[0010] The motor may be disposed within the fixed wing.

[0011] The angle gearbox may be connected via a first shaft rotatable about a first axis oriented towards the motor and a second shaft rotatable about a second axis oriented along the hinge line, the first axis and the second axis forming a significant angle.

[0012] The first axis may form an angle between 70 degrees and 90 degrees with the second axis.

[0013] The second shaft can be directly coupled to all of the plurality of gear-driven mechanical actuators. Alternatively, the second shaft can be split at an angle gearbox, and a first portion of the second shaft can be directly coupled to one or more of the gear-driven mechanical actuators, and a second portion of the second shaft can be directly coupled to one or more of the gear-driven mechanical actuators.

[0014] The angle gearbox can provide gear reduction.

[0015] The actuation system can further include another gearbox coupled between the motor and the angle gearbox, the another gearbox providing gear reduction.

[0016] The actuation system can further include a clutch located between the motor and the plurality of gear-driven mechanical actuators for mechanically disconnecting the motor from the plurality of gear-driven mechanical actuators.

[0017] The actuation system can further include a brake located between the motor and the plurality of gear-driven mechanical actuators for preventing movement of the plurality of gear-driven mechanical actuators.

[0018] Preferably, the fixed wing has a leading edge and a trailing edge, and the wingtip device has a leading edge and a trailing edge, and wherein the plurality of gear-driven mechanical actuators are all disposed between the leading edge and the trailing edge of the fixed wing and between the leading edge and the trailing edge of the wingtip device.

[0019] Preferably, the fixed wing has a front spar and a rear spar, and the wingtip device has a front spar and a rear spar, and wherein the plurality of gear-driven mechanical actuators are all disposed between the front spar and the rear spar of the fixed wing and between the front spar and the rear spar of the wingtip device.

[0020] The motor can have an output shaft oriented generally parallel to the spanwise axis of the fixed wing.

[0021] The motor can be disposed within the fixed wing near the location of the maximum thickness of the airfoil profile of the wing.

[0022] Each gear-driven mechanical actuator can have a first knuckle fixed to the fixed wing and a second knuckle fixed to the wingtip device, wherein the first knuckle and the second knuckle are driven to rotate relative to each other by the gear-driven mechanical actuator using motive power provided by the motor.

[0023] Preferably, the fixed wing has an upper surface and a lower surface, and the wingtip device has an upper surface and a lower surface, and the wingtip device is operable between the following configurations: (i) a fixed flight configuration for use during flight, in which the upper surface and the lower surface of the wingtip device are substantially fixed relative to the upper surface and the lower surface of the fixed wing; and (ii) a movable flight configuration for use during flight, in which the wingtip device moves relative to the fixed wing such that at least one of the upper surface and the lower surface of the wingtip device moves away from the corresponding surface of the fixed wing.

[0024] The actuation system may further include a restraint assembly operable between a restraint mode and a release mode, in which the restraint force is used to hold the wingtip device in the fixed flight configuration in the restraint mode, and in which the restraint force on the wingtip device is released in the release mode such that the wingtip device can adopt the movable flight configuration.

[0025] The upper surface and the lower surface of the wingtip device may be continuous with the upper surface and the lower surface of the fixed wing when the wingtip device is in the fixed flight configuration.

[0026] To reduce the load, or when the aircraft speed reaches a threshold just below the static aeroelastic divergence speed of the wing, or when the aircraft is flying at a relatively low speed or altitude and a relatively high roll rate is required, the wing can be operated in the movable flight configuration. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Embodiments of the present invention will now be described with reference to the drawings, in which:

[0028] FIG. 1 shows a plan view of an aircraft having a wing and a forward-swept folding wingtip device;

[0029] Figure 1b Is shown in detail Figure 1a The wingtip device of;

[0030] Figure 2a Shows Figure 1a A front view of the aircraft of, in which the wingtip device is in various configurations;

[0031] Figure 2b , Figure 2c And Figure 2d Is shown in detail Figure 2a The wingtip device of;

[0032] Figure 3a And Figure 3b Show front views of various other configurations of the wingtip device;

[0033] Figure 4a And Figure 4bShows a comparative actuation system for moving a wingtip device that is not according to the present invention;

[0034] Figure 5a and Figure 5b Shows a first embodiment of an actuation system for moving a wingtip device according to the present invention;

[0035] Figures 6 to 8 Shows an exploded view of various actuation systems compatible with the present invention; and

[0036] Figure 9 Shows a second embodiment of an actuation system for moving a wingtip device according to the present invention. Detailed Description

[0037] Figure 1a Is a plan view of an aircraft 1. The aircraft includes a central fuselage 3 and two main wings 5 extending outwardly from respective wing roots 5'.

[0038] Each wing 5 includes a fixed wing 7 extending from the root 5' to the tip 7' (shown in close-up in Figure 1b ). At the tip 7' of the fixed wing 7, the wing 5 also includes a movable wingtip device 9 in the form of a flat wingtip extension. The wingtip device 9 is rotatably mounted about a hinge 11. The hinge 11 is oriented not parallel to the flight direction line (or splayed outwardly relative to the flight direction line). The hinge 11 may alternatively be parallel to the flight direction line.

[0039] In a fixed flight configuration, the wingtip device 9 is fixed relative to the fixed wing 7. The wingtip device 9 may be an extension of the fixed wing. Thus, the upper and lower surfaces of the fixed wing 5 may be continuous with the upper and lower surfaces of the wingtip device 9 (see Figure 2b and Figure 2a for the lowermost position). The leading and trailing edges of the fixed wing 5 are also continuous with the corresponding leading and trailing edges of the wingtip device 9 (see Figure 1a and Figure 1b ). Such an arrangement is advantageous because it provides a relatively large wingspan of the aircraft wing, thereby providing an aerodynamically efficient aircraft.

[0040] However, a larger wingspan may result in a correspondingly larger load on the wing 5, especially a larger wing root bending moment, particularly during high load events such as gusts or extreme maneuvers. Such a larger wing root bending moment is a problem for relatively large wingspan wings. The wing 5 must be sized to cope with these maximum loads that may result in a relatively heavy wing, and a relatively heavy wing may not be allowed.

[0041] The wingtip device 9 is in a mobile flight configuration (seeFigure 2a and Figure 2c ) the ability to move substantially freely in an attempt to solve this problem. In this configuration, the wingtip device 9 can rotate substantially freely about the hinge 11.

[0042] As Figure 2c shown in and Figure 2a the intermediate position in, the wingtip device 9 can rotate upward so that the lower surfaces between the fixed wing 7 and the wingtip device 9 are no longer continuous with each other. In addition, if the hinge 11 is angled relative to the oncoming airflow direction (i.e., opposite to the line of the flight direction F) when the wingtip device 9 rotates upward, the average angle of attack of the wingtip device 9 decreases.

[0043] In this mobile flight configuration, the loads generated by the wingtip device 9 on the wing 5 are significantly reduced. The wingtip device 9 can be released to this configuration during flight (described in more detail below). By providing this load alleviation function during flight, the maximum load for which the wing needs to be designed can be reduced, and thus the wing 5 can be manufactured relatively lightly.

[0044] The wingtip device 9 can also be configured in a ground configuration in which the wingtip device 9 is further rotated to a substantially upright position (shown in the upright position in Figure 2d and Figure 2a ). The wingtip device can be moved to this configuration when it is on the ground (described in more detail below). Once rotated to this position, the wingspan of the aircraft 1 is sufficient to meet the boarding gate restrictions for airport compatibility. Thus, the aircraft 1 can have a large wingspan (exceeding the boarding gate restrictions) during flight, but still be able to comply with the boarding gate restrictions when on the ground.

[0045] As Figure 3a and Figure 3b shown in, the hinge 111 can be a double hinge that allows the wingtip device 9 to rotate upward and downward in the mobile flight configuration ( Figure 6 only the downward rotation is illustrated in b, and according to Figure 2c is the upward rotation). This arrangement enables both positive g loads and negative g loads to be alleviated. The additional functions of the hinge 111 can be combined with the above-described hinge 11.

[0046] Figure 4a and Figure 4bA comparative example of an actuation system 20 for rotating a wingtip device 9 about a hinge 11 is shown. The actuation system includes a motor 22, a plurality of gear-driven mechanical actuators 24, and a gearbox 26. The motor 22 may form part of a power drive unit (PDU) incorporating a brake, or may be provided with a separate brake. The gear-driven mechanical actuators are rotary actuators arranged to convert a first rotary motion into a different second rotary motion, for example, at different angular rotation rates and / or torques and / or directions.

[0047] In the illustrated comparative example, there are three gear-driven rotary actuator (GRA) "slices". The three GRAs are driven by a common shaft connection via the gearbox 26, which is a pre-stage reduction gearbox. The motor 22 (or PDU) is arranged at one end of the three GRA slices. The GRAs 24 are each arranged on the hinge line of the hinge 11.

[0048] Each of the GRAs 24 has a first knuckle 24a (or a pair of first knuckles) connected to the fixed wing 7 and a second knuckle 24b (or a pair of second knuckles) connected to the wingtip device 9. Each of the GRAs 24 is substantially the same. When the motor 22 is activated to drive the common drive shaft (not visible) via the gearbox 26, the second knuckle 24b rotates relative to the first knuckle 24a of the GRA 24. This drives the wingtip device 9 to articulate relative to the fixed wing about the hinge 11. The rotation can be positive or negative.

[0049] A clutch 28 is provided between the gearbox 26 and the GRA 24. Engaging the clutch enables the motor 22 to drive the GRA 24. When the brake (the brake of the PDU) is engaged and the clutch 28 is also engaged, the brake is activated to prevent the wingtip device 9 from rotating relative to the fixed wing about the hinge 11.

[0050] Disengaging the clutch enables the GRA 24 to rotate substantially freely, thereby allowing the wingtip device 9 to rotate substantially freely relative to the fixed wing about the hinge 11 when in a moving flight configuration.

[0051] Once the brake and clutch are released, the wingtip device can be actuated completely passively in a moving flight configuration. For example, the wingtip device can move under the action of aerodynamic forces and / or gravity. The choice to brake or release the wingtip device can be referred to as a "semi-aeroelastic" arrangement.

[0052] Figure 4a A schematic plan view of the actuation system 20, the wingtip device 9, and the fixed wing 7 is shown, and Figure 4bA schematic front view of the actuation system 20, the wingtip device 9, and the fixed wing 7 is shown. As can be seen, a representative fairing 30 is shown in dashed lines and is sized to accommodate the actuation system 20. The fairing 30 extends significantly above the upper wing surface, below the lower wing surface, in front of the wing leading edge, and behind the wing trailing edge. Figure 4a and Figure 4b the fairing 30 in the comparative example of

[0053] Figure 5a and Figure 5b A first embodiment of an actuation system 20' for rotating the wingtip device 9 about the hinge 11 is shown. The actuation system 20' is functionally substantially the same as the above-described actuation system 20 in the comparative example, and like reference numerals are used to denote like parts. Like reference numerals with an apostrophe (') are used to denote parts similar to those in the comparative example that are different in their size and / or position but substantially share the same function as described above.

[0054] The actuation system 20' includes a motor 22', a plurality of gear-driven mechanical actuators 24', and a gearbox 26'. The motor 22' may form part of a power drive unit (PDU) incorporating a brake or may be provided with a separate brake.

[0055] In the actuation system 20', there are four gear-driven rotary actuator (GRA) "slices" each arranged on the hinge line of the hinge 11. The four GRAs are driven via a gearbox 26' which is a pre-stage reduction gearbox. The GRA 24' is functionally substantially the same as the above-described GRA 24 but has a smaller diameter than the GRA 24. The torque output of the four GRAs 24' can be substantially the same as the torque output of the three GRAs 24, and thus the ability of the actuation system 20' to rotate the wingtip device 9 relative to the fixed wing about the hinge 11 can be substantially the same as that of the actuation system 20. This enables the actuation system to drive the wingtip device 9 from a mobile flight configuration or a ground configuration to a fixed flight configuration.

[0056] Importantly, the actuation system 20' differs from the actuation system 20 in that there is an additional angular gearbox 29 coupled between the plurality of GRAs 24' and the motor 22'. The angular gearbox 29 has an input shaft 32 extending away from the hinge 11 towards the motor 22'. The angular gearbox 29 is arranged along the hinge line of the hinge 11. The angular gearbox 29 enables the motor 22' to be positioned away from the hinge 11.

[0057] Increasing the number of GRA slices 24' from three to four results in each GRA slice 24' being smaller in size (diameter) than the GRA slices 24 of the comparative example. As Figure 5bAs can be seen, this has the effect of reducing the overall height of the actuation system 20' at the hinge 11, so that the size of the fairing 30' in the height dimension is smaller than that of the comparative fairing 30 (shown in Figure 5b in light dashed lines). This enables the actuation system 20' and the associated fairing 30' to have a smaller frontal profile area, which can help reduce drag.

[0058] Increasing the number of GRA slices 24' from three to four also occupies more of the chord length between the leading edge and the trailing edge of the wing at the hinge 11, which is contrary to the intention of reducing drag. Additionally, driving all four GRA slices 24' on a common shaft from one end may introduce mechanical inefficiencies and higher mechanical resistance in the actuation system. The angle gearbox 29 addresses both of these issues.

[0059] The angle gearbox 29 is arranged along the hinge line of the hinge 11 and is disposed between two of the GRAs 24'. Thus, the motor 22' can be positioned in the fixed wing 7 away from the hinge 11, and the GRAs 24' are separated in the direction of the hinge 11 into a pair of front GRAs 24' located in front of the angle gearbox 29 and a pair of rear GRAs 24' located behind the angle gearbox 29. Thus, the potential mechanical inefficiencies of driving all four GRAs 24' from one end are avoided.

[0060] In addition to the motor 22' and the brake (or PDU), the gearbox 26' and the clutch 28' can be located within the fixed wing 7. Thus, compared to the actuation system 20, the length of the entire actuation system 20' at the hinge can be reduced.

[0061] The angle gearbox 29 can be a reduction gearbox. With the reduction angle gearbox 29, the amount of gear reduction required in the pre-stage gearbox 26' is reduced. Thus, the size (diameter) of the gearbox 26' can also be reduced. This helps to fit the pre-stage gearbox 26' within the profile of the fixed wing 7. The gearbox 26' can be oriented with its length dimension substantially in the wing spanwise direction S. The gearbox 26' can also trade length for diameter to help fit the pre-stage gearbox 26' within the profile of the fixed wing 7.

[0062] The clutch 28' can be sized according to the load transmitted from the motor 22' when the motor 22' drives the wingtip device 9. Due to the gear ratio of the reduction gearbox 29 between the GRA 24' and the clutch 28', the clutch 28' can be significantly smaller than the clutch 28 acting directly on the GRA 24. The smaller clutch 28' helps to fit the clutch 28' within the profile of the fixed wing 7. The clutch 28' can be oriented with its length dimension substantially in the wing spanwise direction.

[0063] The smaller clutch 28' and the smaller pre-stage gearbox 26' can be lighter than the clutch 28 and the gearbox 26, which will be beneficial in terms of aircraft class and can also reduce local dynamic loads.

[0064] The motor 22' and the brake (or PDU) can be only slightly smaller than the corresponding parts in the actuation system 20.

[0065] Since the clutch 28', the pre-stage gearbox 26' and the motor 22' (or PDU) no longer protrude from the trailing edge of the GRA at the hinge, the length of the actuation system 20' at the hinge 11 is reduced, so that the size of the fairing 30' in the length (chordwise) dimension is smaller than that of the comparison fairing 30 (shown in Figure 5a in light dashed lines). This makes the actuation system 20' and the associated fairing 30' have a smaller profile area, which can help reduce drag.

[0066] In addition, since the clutch 28', the pre-stage gearbox 26' and the motor 22' (or PDU) no longer protrude from the trailing edge of the GRA at the hinge, the risk of adverse vibration at the hinge can also be reduced.

[0067] The clutch 28', the pre-stage gearbox 26' and the motor 22' (or PDU) will pass through the wing box rib, which may require a reduced space for the fuel tank volume. This potential disadvantage is the trade-off of the lower drag of the smaller size of the actuation system 20' and the fairing 30'.

[0068] Disengaging the clutch 28' enables the GRA 24' to rotate essentially freely, thereby allowing the wingtip device 9 to rotate essentially freely relative to the fixed wing about the hinge 11 when in the mobile flight configuration.

[0069] Engaging the clutch 28' enables the motor 22' to drive the GRA 24'. When the brake (the brake of the PDU) is engaged and the clutch 28' is also engaged, the brake is activated to prevent the wingtip device 9 from rotating relative to the fixed wing about the hinge 11 in the fixed flight configuration.

[0070] Depending on the deployment angle of the hinge 11 relative to the wing spanwise direction S, the input shaft 32 of the angle gearbox 29 may have a bend, as shown in Figure 5a as shown. The bend can be provided by a CV joint or the like.

[0071] Figure 6 Shown according to Figure 5a and Figure 5bExploded view of some components of the actuation system 20' of the first arrangement compatible with the embodiment. The actuation system 20' has four GRAs 24' driven by the common output shaft 34 of the angle gearbox 29. Along the hinge 11, the first pair of GRAs 24' is located on one side of the angle gearbox 29, and the second pair of GRAs 24' is located on the opposite side of the angle gearbox 29. The common output shaft 34 extends through each of the four GRAs 24' and through the angle gearbox 29. The input shaft 32 has an axis that extends approximately 90 degrees relative to the axis of the common output shaft 34. The angle gearbox 29 may include engaged bevel gears or an analogue that couples the input shaft and the output shaft in a gear-rotating manner. The angle formed by the input shaft and the output shaft may be between 70 degrees and 90 degrees.

[0072] Figure 7 Shows according to Figure 5a and Figure 5b Alternative exploded view of some components of the actuation system 20' of the second arrangement compatible with the embodiment. The actuation system 20' has four GRAs 24' driven by a separate output shaft of the angle gearbox 29, which separate output shaft includes a first output shaft portion 34a and a second output shaft portion 34b. Along the hinge 11, the first pair of GRAs 24' is located on one side of the angle gearbox 29, and the second pair of GRAs 24' is located on the opposite side of the angle gearbox 29. The first output shaft portion 34a extends through the first pair of GRAs 24' and extends into (but not through) the angle gearbox 29. The second output shaft portion 34b extends through the second pair of GRAs 24' and extends into (but not through) the angle gearbox 29. The input shaft 32 has an axis that extends approximately 90 degrees relative to the axis of the separate output shaft. The angle gearbox 29 may include engaged bevel gears or an analogue that couples the input shaft and the output shaft portions in a gear-rotating manner. The angle formed by the input shaft and the output shaft may be between 70 degrees and 90 degrees.

[0073] Figure 8 Another alternative exploded view of some components of the actuation system 20' according to the third arrangement. The actuation system 20' is similar in most respects to the actuation systems of the first and second arrangements described above, but includes five GRAs 24' instead of four, and the angle gearbox 29 is located between a pair of front GRAs 24' and three rear GRAs 24'. Thus, the separate output shaft has a first shaft portion 34a and a longer second shaft portion 34c. The GRAs 24', the angle gearbox 29, and the shafts may have different sizes, but their arrangement and function are basically the same as those described above, and are compatible with Figure 5a and Figure 5b the embodiment.

[0074] It will be understood that in other alternative variants, the number of GRA24' in the actuation system can be increased to more than five.

[0075] Since the input shaft 32 is positioned more forward along the hinge 11, the motor 22' can be positioned more forward in the fixed wing 7. The motor can advantageously be arranged within the fixed wing near the position of the maximum thickness of the airfoil profile of the wing to more easily accommodate the motor 22', the gearbox 26' and the clutch 28'. This may affect the trade-off between the diameter and the length of these components, which may result in a shorter length but a larger diameter without affecting the wing profile. As emphasized above, the shorter length of at least some of these components can reduce the negative impact on the fuel volume of the wing.

[0076] Figure 9 A second embodiment of an actuation system 20” for rotating the wing tip device 9 about the hinge 11 is shown. The actuation system 20” is functionally substantially the same as the above-described actuation system 20' in the first embodiment, and like reference numerals are used to denote like parts. Like reference numerals with double primes (”) are used to denote parts similar to those in the first embodiment that differ in their size and / or position but substantially share the same function as described above.

[0077] The actuation system 20” differs from the actuation system 20' in that the angle gearbox 29 is located between one front GRA24' and three rear GRA34' among the GRA24' on the hinge 11. Accordingly, the input shaft 32, the motor 22' (and the brake or PDU), the gearbox 26' and the clutch 28' are all relatively more forward towards the leading edge of the fixed wing 7. In all other respects, the actuation system 20” is the same as the actuation system 20'. Compared with Figure 5a and Figure 5b the first embodiment of, the size of the actuation system at the hinge 11 is not affected, and thus neither is the fairing 30', thereby retaining all of the aforementioned advantages.

[0078] Similar to Figure 8 the variant shown in Figure 9 a further benefit of the second embodiment of is that since the input shaft 32 is positioned more forward along the hinge 11, the motor 22' can be positioned more forward in the fixed wing 7. The motor can advantageously be arranged within the fixed wing near the position of the maximum thickness of the airfoil profile of the wing to more easily accommodate the motor 22', the gearbox 26' and the clutch 28'. This may affect the trade-off between the diameter and the length of these components, which may result in a shorter length but a larger diameter without affecting the wing profile. As described above, the shorter length of at least some of these components can reduce the negative impact on the fuel volume of the wing.

[0079] The "actuation system 20" may have a common output shaft 34 similar to the first arrangement of FIG. 5, or may have separate output shafts similar to the second or third arrangements of Figure 7 and Figure 8 FIG..

[0080] In the above embodiments and examples, the fixed wing 7 has a leading edge 41 and a trailing edge 42, and the wingtip device 9 has a leading edge 51 and a trailing edge 52, and the GRA 24' is disposed between the leading edge and the trailing edge of the fixed wing and between the leading edge and the trailing edge of the wingtip device. This ensures that the length of the fairing 30' is minimized.

[0081] In the above embodiments and examples, the fixed wing 7 has a front spar 43 and a rear spar 44, and the wingtip device 9 has a front spar 53 and a rear spar 54, and the GRA 24' is disposed between the front spar and the rear spar of the fixed wing and between the front spar and the rear spar of the wingtip device. This ensures the management of the loads entering the fixed wing and the wingtip device from the GRA without additional structures in front of the front spar or behind the rear spar.

[0082] In the above embodiments and examples, the wingtip device may operate between the following configurations: (i) a fixed flight configuration for use during flight, in which the upper and lower surfaces of the wingtip device are substantially fixed relative to the upper and lower surfaces of the fixed wing; and (ii) a mobile flight configuration for use during flight, in which the wingtip device moves relative to the fixed wing such that at least one of the upper and lower surfaces of the wingtip device moves away from the corresponding surface of the fixed wing.

[0083] In the above embodiments and examples, the brakes and clutches may form part of a limiting assembly of the actuation system, which may operate between a limiting mode and a release mode. In the limiting mode, the wingtip device is held in the fixed flight configuration using a limiting force, and in the release mode, the limiting force on the wingtip device is released such that the wingtip device can adopt the mobile flight configuration.

[0084] In the above embodiments and examples, the upper and lower surfaces of the wingtip device may be continuous with the upper and lower surfaces of the fixed wing when the wingtip device is in the fixed flight configuration.

[0085] In the above embodiments and examples, in order to relieve the load, or when the aircraft speed reaches a threshold just below the static aeroelastic divergence speed of the wing, or when the aircraft is flying at a relatively low speed or altitude and a relatively high roll rate is required, the wing may operate in the mobile flight configuration.

[0086] When the term "or" appears, this will be interpreted as meaning "and / or", such that the items referred to are not necessarily mutually exclusive and may be used in any suitable combination.

[0087] Although the invention has been described above with reference to one or more preferred embodiments, it will be understood that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.

Claims

1. An aircraft wing, comprising: A fixed wing having a tip; And a wing tip device rotatably mounted on a hinge at the tip of the fixed wing such that the wing tip device can rotate about the hinge; And an actuation system for rotating the wing tip device about the hinge, wherein the actuation system includes a motor, a plurality of gear-driven mechanical actuators, and an angle gearbox coupled between the plurality of gear-driven mechanical actuators and the motor, each gear-driven mechanical actuator being drivable by the motor and arranged to convert a rotational motion into a different rotational motion, each gear-driven mechanical actuator being arranged along the hinge line of the hinge, and wherein the angle gearbox is arranged along the hinge line and arranged between two of the plurality of gear-driven mechanical actuators.

2. The aircraft wing according to claim 1, wherein, The actuation system includes at least four gear-driven mechanical actuators.

3. The aircraft wing according to claim 1 or claim 2, wherein, The motor is disposed within the fixed wing.

4. The aircraft wing according to any one of the preceding claims, wherein, The angle gearbox is connected via a first shaft rotatable about a first axis oriented towards the motor and a second shaft rotatable about a second axis oriented along the hinge line, the first axis and the second axis forming a significant angle.

5. The aircraft wing according to claim 4, wherein, The first axis and the second axis form an angle between 70 degrees and 90 degrees.

6. The aircraft wing according to claim 4 or claim 5, wherein, The second shaft is directly coupled to all of the plurality of gear-driven mechanical actuators, or wherein the second shaft splits at the angle gearbox and a first portion of the second shaft is directly coupled to one or more of the gear-driven mechanical actuators and a second portion of the second shaft is directly coupled to one or more of the gear-driven mechanical actuators.

7. The aircraft wing according to any one of the preceding claims, wherein, The angle gearbox provides gear reduction.

8. The aircraft wing according to any one of the preceding claims, wherein, The actuation system further includes another gearbox coupled between the motor and the angle gearbox, the another gearbox providing gear reduction.

9. The aircraft wing according to any one of the preceding claims, wherein, The actuation system further includes a clutch located between the motor and the plurality of gear-driven mechanical actuators for mechanically disconnecting the motor from the plurality of gear-driven mechanical actuators.

10. The aircraft wing according to any one of the preceding claims, wherein, The actuation system further includes a brake located between the motor and the plurality of gear-driven mechanical actuators for preventing movement of the plurality of gear-driven mechanical actuators.

11. The aircraft wing according to any one of the preceding claims, wherein, The fixed wing has a leading edge and a trailing edge, and the wing tip device has a leading edge and a trailing edge, and wherein the plurality of gear-driven mechanical actuators are all disposed between the leading edge and the trailing edge of the fixed wing and between the leading edge and the trailing edge of the wing tip device.

12. The aircraft wing according to any one of the preceding claims, wherein, The fixed wing has a front spar and a rear spar, and the wing tip device has a front spar and a rear spar, and wherein the plurality of gear-driven mechanical actuators are all disposed between the front spar and the rear spar of the fixed wing and between the front spar and the rear spar of the wing tip device.

13. The aircraft wing according to any one of the preceding claims, wherein, The motor has an output shaft oriented substantially parallel to the spanwise axis of the fixed wing.

14. The aircraft wing according to any one of the preceding claims, wherein, The motor is disposed within the fixed wing near the location of the maximum thickness of the airfoil profile of the wing.

15. The aircraft wing according to any one of the preceding claims, wherein, Each gear-driven mechanical actuator has a first knuckle fixed to the fixed wing and a second knuckle fixed to the wingtip device, wherein the first knuckle and the second knuckle are driven to rotate relative to each other by the gear-driven mechanical actuator using motive power provided by the motor.

16. The aircraft wing according to any one of the preceding claims, wherein, The fixed wing has an upper surface and a lower surface, and the wingtip device has an upper surface and a lower surface, and the wingtip device is operable between the following configurations: (i) a fixed flight configuration for use during flight, in which the upper surface and the lower surface of the wingtip device are substantially fixed relative to the upper surface and the lower surface of the fixed wing; and (ii) a moving flight configuration for use during flight, in which the wingtip device moves relative to the fixed wing such that at least one of the upper surface and the lower surface of the wingtip device moves away from the corresponding surface of the fixed wing.

17. The aircraft wing according to claim 16, wherein, The actuation system further includes a restraint assembly operable between a restraint mode and a release mode, in which, in the restraint mode, the wingtip device is held in the fixed flight configuration using a restraining force, and in the release mode, the restraining force on the wingtip device is released to enable the wingtip device to assume the moving flight configuration.

18. The aircraft wing according to claim 16 or claim 17, wherein, The upper surface and the lower surface of the wingtip device are continuous with the upper surface and the lower surface of the fixed wing when the wingtip device is in the fixed flight configuration.

19. An aircraft wing according to any one of claims 16 to 18, wherein, To reduce the load, or when the aircraft speed reaches a threshold just below the static aeroelastic divergence speed of the wing, or when the aircraft is flying at a relatively low speed or altitude and a relatively high roll rate is required, the wing is operable in the moving flight configuration.

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