Hinge structure

Abstract

A spar structure can connect a moveable component to an aircraft. The structure is formed from a single continuous body of material defining a plurality of attachment/actuation brackets and a pair of continuous hinge lines extending through the body.

Claims

1. A method of manufacturing a spar structure for connecting a moveable component to an aircraft, the spar structure comprising a continuous body of material defining a plurality of attachment and actuation brackets and a pair of continuous hinge lines extending through the body, the method comprising the steps of: (A) drilling a pair of elongate bores into a block or billet of material to define the pair of continuous hinge lines; and (B) machining the block or billet of material according to a predetermined machining profile to form the spar structure around the pair of continuous hinge lines.

2. The method of claim 1, wherein drilling the pair of elongate bores includes a deep hole drilling process.

3. The method of claim 2, wherein the deep drilling process is a gun-drilling process.

4. The method of claim 2, wherein the block or billet of material is caused to counter-rotate relative to a direction of rotation of the drilling process during the drilling process.

5. The method of claim 2, further comprising including the spar structure in an aircraft wing.

Description

DRAWINGS

(1) Aspects of the disclosure will now be described, by way of example only, with reference to the accompanying figures in which:

(2) FIG. 1 shows a schematic of a moveable structure of an aircraft wing;

(3) FIG. 2 shows a pivot and actuator arrangement for a moveable structure;

(4) FIG. 3 shows a wing aileron and positions of actuation and hinge brackets;

(5) FIG. 4 shows an integrated spar and aileron;

(6) FIG. 5 shows a closer view of the integrated spar of FIG. 4; and

(7) FIG. 6 shows a billet, integrated spar and pivot lines.

(8) While the claimed invention is susceptible to various modifications and alternative forms, specific embodiments are shown by way of example in the drawings and are herein described in detail. It should be understood however that drawings and detailed description attached hereto are not intended to limit the invention to the particular form disclosed but rather the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the claimed invention

(9) It will be recognised that the features of the aspects of the invention(s) described herein can conveniently and interchangeably be used in any suitable combination. It will also be recognised that the disclosure covers not only individual embodiments but also combinations of the embodiments that have been discussed herein.

DETAILED DESCRIPTION

(10) FIG. 1 is a schematic end view of an aircraft wing 1 viewed in cross-section towards the fuselage of the aircraft. The wing comprises a leading edge 2 and a trailing edge 3. FIG. 1 illustrates one example of a moveable structure on a conventional aircraft. The structure shown is an aileron 4 which is movable about a pivot proximal to the trailing edge of the main wing box 5. The arrows illustrate how the aileron can then be moved about the pivot. Movement causes the distal part of the aileron from the pivot to move in an arc which in the case of the aileron allows the aircraft to roll and turn.

(11) FIG. 1 represents just one location of a moveable component on an aircraft structure. Other examples include wing flaps, the tail wings, tail rudder and even the landing gear doors. It will be recognized that the arrangements and methods described herein can be applied to any hinged arrangement for an aircraft structure.

(12) FIG. 2 is a cross-section through the pivot connection of the aileron in FIG. 1. The aileron 4 is rotatably mounted to a pivot 6. The pivot 6 extends along the aileron as described below. Movement of the aileron 4 about the pivot 6 causes the aileron to move in an arc in the direction of the arrows.

(13) The aileron is provided with a second pivot 7 which is coupled to an actuator 8 comprising and extendable rod or arm 9 which can extend or retract in the direction of the arrows shown. The actuator 8 and arm 9 may be any suitable combination for use on an aircraft. One example is a hydraulic pump driving a threaded rod. Thus, rotation of the drive causes movement of the rod. Because the pivot 6 and pivot 7 are offset movement of the rod 9 causes movement of the aileron about the pivot 6. The actuator and rod are housed within the wing box 5.

(14) FIG. 2 is a cross-section through one pivot and actuator arrangement. To support the aileron along its length (which could in some aircraft be in excess of 3 metres long) the hinge arrangement and actuator attachments need to be positioned at multiple points along the aileron/wing box. FIG. 3 illustrates a six point hinge coupling.

(15) In FIG. 3 the aileron 4 is coupled to the wing box 5 at 6 discrete points 10A, 10B, 10C, 10D, 10E and 10F. Actuation points are not required at every position and so, as an example, the actuator points may be positions 10B and 10D and the remaining positions may be hinge or pivot points. This advantageously allows for redundancy in the hinge should one connection fail and further equally supports the aileron along its length.

(16) As discussed above, the aileron may be in excess of 3 metres in length and so accurate alignment of the pivot line extending through each of the coupling points 10A to 10F is essential for the accurate operation of the aileron.

(17) Conventionally, this precise alignment is achieved by positioning each of the brackets that form the pivot 6 connection and the actuator pivot 7 connection in a specially manufactured jig before assembly. A shaft can then be passed through each of the bores in the brackets to form the elongate pivot lines of pivot 6 and pivot 7.

(18) However, as also set out above this is intensely time consuming and skill is needed to meet the required interchangeability (ICY) tolerances. Fettling and shimming techniques are used to ensure ICY compliance in a conventional arrangement.

(19) Conventional connection arrangements as described above advantageously allow the separate hinge & actuator attachment brackets to be removed and repaired individually during service life (using a suitable jig to re-achieve the hinge line). Disadvantageously, the arrangements are labour intensive assembly tasks, resulting in high recurring cost, high parts count and manufacturing tolerance variables multiplied with number of separate parts.

(20) The specifics of the alternative coupling arrangement will now be described.

(21) FIG. 4 shows the integrated and continuous hinge coupling arrangement according to examples described herein. An integrated or continuous front spar 11 for the aileron 4 is provided.

(22) The terms integrated/continuous are intended to refer to a component which is formed as a single body of material. Specifically, the integrated spar 11 may be formed by machining a single billet of material to form the body of the spar 11 and each of the hinge or actuator attachments 10A, 10B, 10C, 10D, 10E, 10F, 10G which allow the aileron to be both coupled to the wing box (not shown in FIG. 4) and also actuated to cause movement of the aileron relative to the wing box.

(23) Alternatively, the integrated spar 11 may be formed using additive manufacturing techniques to form the spar 11 as a single unsegregated component incorporating a rigid outer body supporting the plurality of hinge and actuator brackets 10A, 10B, 10C, 10D, 10E, 10F. 10G.

(24) FIG. 4 shows the integrated spar 11 and aileron separated. However, in use the spar 11 is coupled to the front edge 12 (the leading edge) of the aileron 4. The arrangement in FIG. 4 is configured to replicate the locations of the hinge and actuator attachment brackets shown in FIG. 3, namely connections 10A, 10B, 10C, 10D, 10E, 10F with the addition of a further hinge position 10G. The integrated spar 11 is a single component and may be coupled to the aileron leading edge in any suitable way.

(25) FIG. 5 shows the integrated spar 11 in more detail at one end. The hinge and actuator brackets can be seen to replicate the couplings 10A, 10B and 10C shown in FIG. 3.

(26) FIG. 5 also illustrates the spatial separation of the two hinge lines 6 and 7. Pivot line 6 represents the pivot line of the aileron and pivot line 7 represents the pivot of the actuator connection. It will be recognised that the shaft passing through the pivot line 7 (connecting the actuator to the integrated spar) will itself rotate about the pivot line 6 as the actuation occurs.

(27) Any suitable configuration of hinge brackets and actuation brackets can be positioned along the length of the integrated spar just as in a conventional connection arrangement.

(28) As stated above the integrated spar 11 may be advantageously formed form a single billet of material. Using a suitable CNC milling machine a billet of aluminium (as one example) may be machined to create the integrated spar. Machined material can be recycled optimising material usage and additionally the spar geometry can be optimised for rigidity and strength.

(29) Advantageously this integrated spar arrangement overcomes the disadvantage of manufacturing the current assembled hinge & actuator attachment brackets, by machining all required attachment brackets in a single bracket. The required attachment brackets (also called lugs/clevises) are then machined as integrated features. This process removes the requirement for complex drill/ream support if the process were reversed, as would be normal practise.

(30) Furthermore, the arrangement provides for a reduction in assembly time and associated costs to achieve the required hinge line tolerances.

(31) Thus, a fully integrated spar is provided. It will be recognised that this disclosure extends to a method of manufacturing such an integrated spar arrangement from a single billet of material or using an additive manufacturing technique.

(32) It has further been established that the approach described above allows for a still further advantageous manufacturing approach to be used, as will be described below. Specifically, before machining the billet to form the brackets and structure of the integrated spar highly accurate hinge or pivot lines can be achieved by pre-drilling these in the billet in advance of the machining operation described above. This is illustrated with reference to FIG. 6.

(33) The integrated spar 11 is shown in FIG. 6 within the surrounding billet 12. The billet is a continuous block of material from which the spar 11 can be machined as described above.

(34) Advantageously before performing the machining to form the spar an unconventional approach can be adopted of first drilling the long holes or bores that will form the pivot lines 6 and 7 shown in FIG. 6. Once the bores are formed the integrated spar can then be machined. In effect a multi-stage process is performedfirst form the pivots and then form the structure around the pivot lines.

(35) Advantageously one of the pair of hinge lines 6 may intersect with a first group 13 of said attachment/actuation brackets 10A, 10C, 10E, 10F, 10G and a second of said hinge lines 7 may intersect with a second group 14 of said attachment/actuation brackets 10B, 10D. Adjacent brackets need not be for the same purpose and structural redundancy can be built into the spar should any one bracket fail in any way.

(36) Specifically, the first group of attachment/actuation brackets 13 may be brackets 10A, 10C, 10E, 10F, 10G arranged in use to pivotally mount the moveable component to an aircraft structure. This defines the line or axis 6 around which the movable component rotates, e.g., the aileron.

(37) Similarly, the second group of attachment/actuation brackets 14 may be brackets 10B, 10D arranged in use to couple the spar structure to an actuator. The actuator, for example a linear actuator or similar, can thus be coupled to the spar structure 11. Movement of the second group of brackets 14 by means of the actuator causes the rotation of the spar 11 (and moveable component) around the axis or hinge line 7 described above.

(38) Thus, by means of the pair of hinge lines 6, 7 extending through the body and intersecting with two groups of brackets 13, 14 the spar 11 can be both securely coupled to the wing (for example) and simultaneously allowed to rotate in response to selective control of the actuator.

(39) Advantageously each of the hinge lines 6, 7 may define a cylindrical bore 15, 16 through each attachment/actuation bracket 10A, 10B, 10C, 10D, 10E, 10F, 10G they intersect with. Thus, each bracket 10A, 10B, 10C, 10D, 10E, 10F, 10G that intersects with the hinge line 6, 7 will be in perfect alignment with the lengthwise hinge line 6, 7 passing through the spar 11.

(40) Such an approach provides a highly accurate and continuous pivot line around which the brackets can be created without interrupting the precision of the pivot lines. As shown in FIG. 6 the bores need not extend through the entire length of the billet; they only need extend as far as the last bracket using the pivot line. This approach can be applied on all aircraft movable surfaces requiring a tight hinge line tolerance.

(41) Advantageously the bores forming the pivot lines 6, 7 may be formed using a deep drilling process such as a gun drilling process. This allows a bore to be formed that has a high length to diameter ratio as is the base with the pivot line in an aircraft moveable structure hinge.

(42) The gun drilling process involves supplying a coolant along the centre of the drill bit which acts to simultaneously cool the cutting surface and carry the swarf (waste material from the cutting zone) back along the bore and out of the component. Extremely deep holes can be drilled.

(43) Advantageously to still further improve the accuracy of the pivot lines the billet may be counter-rotated about the gun drill axis of rotation. This advantageously maintains an extremely accurate drilled hole and improves the drilling operation. In such a manufacturing process the billet may be first positioned in a jig that allows for rotation about the gun drill axis to form the first pivot line 6 and then the same process can be repeated to form the second pivot line 7, i.e., by rotating the billet about the pivot line 7 during the drilling process. In each case the pivot line acts as the datum about which the billet is rotated. Specifically, using the counter-rotating approach allows tolerances in excess of 1/10.sup.th of a mm which are desirable in the current application.

(44) The manufacturing process and resulting integrated spar provide a single discrete hinge component which has a highly accurate pair of hinge lines to receive the hinge brackets and actuation brackets of the aileron (or other moveable hinged structured). The fact that no alignment of brackets is required means that when attached to a component such as an aileron, the aileron can be replaced with a high level of accuracy, minimal tooling and in a highly efficient manner. This not only provides for efficient routine maintenance of the aircraft but also conveniently allows for rapid repair out of a hangar, for example on the airfield or the like. The arrangement negates the need for complex and expensive jigs and provides a component which can be readily recycled.

(45) To safely install the component all that is required if for the component to be brought to the same temperature as the wing (to avoid any thermal expansion issues) and then installed.

(46) It will be recognised that this disclosure extends to a moveable hinged structure for an aircraft incorporating an integrated spar described herein and specifically to an aircraft aileron comprising a leading edge integrated spar as described herein.