Method and device for replacing skin on curved surface of outer surface of airplane

Abstract

The invention discloses an aircraft surface curved surface skin replacing method and a replacing device thereof, a primary hole is manufactured according to a reverse hole drill bushing, then the coaxiality of a curved surface drill jig hole is verified according to the reverse hole drill bushing and a step pin, finally, a replaceable drill bushing is used for reaming step by step, and accurate skin hole manufacturing is achieved. According to the method, a traditional curved surface skin replacing, assembling and machining method is changed, the difficulty of replacing the curved surface skin is lowered, the requirements for the skill level and experience of an operator are lowered, the scrap proportion of parts is reduced, the rework assembling quality is improved, the rework efficiency is improved, and the rework manufacturing cost is lowered.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft curved surface skins, and in particular relates to a method for replacing aircraft outer curved surface skins and a replacement device thereof. Background Art

[0002] It is impossible to completely avoid the occasional damage to the curved skin during the assembly and processing of the aircraft's exterior and during the service of the aircraft. Since the skin is connected to the fuselage frame with many parts that are not easy to replace and are of high value, when the skin damage cannot meet the design requirements of function and strength, the skin and the connected parts are generally not scrapped together. Therefore, when the aircraft needs to be repaired due to skin damage, it is very necessary to replace the new skin with an assembly processing method that retains the frame parts.

[0003] At present, in the process of hole making and assembly of aircraft curved skin, holes are generally made from one side of the skin to the other side of the frame. Therefore, the space on the side of the curved skin is relatively open, while the space on the side of the frame is relatively narrow. When replacing the curved skin, if the hole is expanded and reamed from one side of the frame, it will be limited by the narrow space, and the vertical drill will be difficult to use. The verticality and coaxiality of the hole cannot be effectively guaranteed, and there is a risk of "8" holes and the phenomenon of one-way clearance exceeding the tolerance after the fastener is installed; if the hole is expanded and reamed from one side of the skin, although the space is open, the coaxiality with the hole on the frame cannot be effectively guaranteed by relying solely on the vertical drill, and there is still a risk of "8" holes or hole diameter exceeding the tolerance. At the same time, due to the large number of holes involved in the skin, it is difficult to ensure that all holes are qualified to meet the design department's requirements for the performance strength of the aircraft by relying on the operator's craftsmanship according to the traditional manual assembly and processing method, which easily leads to the scrapping of a large number of parts. Summary of the invention

[0004] The object of the present invention is to provide a method and a device for replacing the curved surface skin of an aircraft, which can greatly reduce the difficulty of making initial holes in a new skin while ensuring coaxiality with the holes on the skeleton components, and at the same time reduce the requirements on the operator's own level and experience, improve the rework efficiency and assembly quality, and reduce the rework manufacturing cost, so as to solve the problems raised in the above-mentioned background technology.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A method for replacing the curved surface skin of an aircraft: S1: Remove the damaged skin and reposition the new skin, remove the fasteners connecting the skeleton and the damaged curved skin, and reposition the skeleton and the new curved skin according to the jig; S2: Counter-drilling initial holes, using a counter-drill to drill initial holes on the new skin in the operable area on the jig according to the final holes on the skeleton, and installing temporary fasteners to clamp the skin and the skeleton; S3: Hole expansion: on the basis of the initial holes made in the new skin, use a vertical drill and a step drill to expand all the initial holes, and install temporary fasteners to clamp the skin and the frame; S4: Check, use counter-hole drill sleeves, counter-hole drill sleeves, temporary fasteners, etc. to locate the curved surface drilling jig and verify the coaxiality and fix the curved surface drilling jig; S5: Expand and ream the final hole, expand and ream the new skin according to the curved surface drilling template using a replaceable drill sleeve and remove burrs, and install temporary fasteners to clamp the skin and the frame; S6: Finish making holes in the skin, change the position of the curved surface drilling jig, and complete the hole making operations in other areas of the curved surface skin according to S4-S5; S7: countersinking the skin, disassembling and deburring, and then repositioning the frame and the skin countersinking and installing the fasteners on the jig using positioning pins or temporary fasteners; S8: After the replacement and installation of the skin is completed, the frame is removed and the remaining areas on the jig that cannot be operated are countersunk and fasteners are installed according to S2-S6.

[0006] Furthermore, in S4, the gap between the skin and the frame, and the gap between the curved drill jig and the skin are checked with a feeler gauge, a counter-hole drill sleeve is installed on the frame long stringer, and a stepped pin is inserted into the curved drill jig and passed through the skin, the frame and the counter-hole drill sleeve to ensure that the drill jig hole is coaxial with the frame long stringer hole, and the curved drill jig is fixed with a temporary fastener.

[0007] Furthermore, the inner diameter of the replaceable drill sleeve is determined according to the tool specifications in the processing specifications and operation specifications of the relevant machine model, and the final hole diameter required by the drawing and specifications is gradually increased on the basis of the initial hole.

[0008] Furthermore, the curved surface drilling jig is obtained by establishing a curved surface drilling jig model with a corresponding curvature in CATIA based on a three-dimensional model of the processed curved surface skin and processing it through a CNC machine tool.

[0009] Furthermore, the normal direction of the drill sleeve hole on the curved surface drilling jig is processed by a CNC machine tool according to the theoretical normal direction of the hole to ensure the verticality of the hole.

[0010] A device for replacing curved skin on the outer surface of an aircraft, the skin replacement device comprising a curved drill jig, a reverse hole drill sleeve and a replaceable drill sleeve, wherein a side of the curved drill jig close to the skin is completely fitted with the skin, a drill sleeve hole is provided on the curved drill jig, the drill sleeve hole is perpendicular to the fitting surface between the curved drill jig and the skin, the outer diameter of the reverse hole drill sleeve is matched with the aperture of a terminal hole on a skeleton part, and the outer diameter of the replaceable drill sleeve is matched with the diameter of the drill sleeve hole.

[0011] Furthermore, the number of the drill sleeve holes is at least 3, the drill sleeve holes are adjacent and symmetrically arranged, and the position spacing between the drill sleeve holes is consistent with the position spacing of the holes on the aircraft frame.

[0012] Furthermore, the skin replacement device also includes a stepped pin, and the maximum diameter of the stepped pin is adapted to the inner diameter of the drilling template hole.

[0013] Furthermore, the skin replacement device also includes temporary fasteners, spring pins and washers, and the temporary fasteners, spring pins and washers are used to clamp the aircraft frame and the skin.

[0014] Furthermore, the replaceable drill sleeve includes several different inner diameter specifications to achieve step-by-step expansion of the curved surface skin hole.

[0015] Compared with the prior art, the present invention has the following beneficial effects: In the method of the present invention, the initial hole is made according to the reverse hole drill sleeve, and then the coaxiality of the curved surface drill template hole is verified according to the reverse hole drill sleeve and the step pin, and finally the replaceable drill sleeve is used to expand the hole step by step, so as to realize the precise hole making of the skin. The method changes the traditional curved surface skin replacement assembly processing method, reduces the difficulty of replacing the curved surface skin, reduces the requirements for the operator's skill level and experience, reduces the scrap ratio of parts, improves the rework assembly quality, improves the rework efficiency, and reduces the rework manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0017] Figure 1 is a step diagram of the method of the present invention; Figure 2 It is a schematic diagram of the overall structure of the present invention; Figure 3 for Figure 1 A partial enlarged view of Figure 4 A schematic diagram of a partial embodiment of the present invention for making an initial hole in a curved surface skin using a reverse hole drill sleeve; Figure 5 A schematic diagram of a partial embodiment of the present invention of using a step drill and vertical drilling to expand a primary hole; Figure 6 A schematic diagram of a partial embodiment of the coaxiality verification and fixed curved surface drilling jig of the present invention; Figure 7 A schematic diagram of a partial embodiment of the present invention for removing the reverse hole drill sleeve and the stepped pin; Figure 8 A schematic diagram of a partial implementation example of using a replaceable drill sleeve to expand and reame a skin hole provided by the invention In the figure: 1. Skeleton; 2. Skin; 3. Formwork; 4. Curved surface drilling jig; 5. Interchangeable drill sleeve; 6. Temporary fastener; 7. Spring pin; 8. Counter-hole drill sleeve; 9. Drill bit / reamer; 10. Gasket; 11. Vertical drill; 12. Step pin. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0019] It is worth noting that the curved surface drill jig 4 described in the present invention is based on the three-dimensional model of the processed curved surface skin 2, and the curved surface drill jig 4 model with the corresponding curvature is established in CATIA and processed by a CNC machine tool, thereby ensuring the fit between the drill jig and the skin 2. At the same time, the normal of the drill sleeve hole on the curved surface drill jig 4 is also processed by a CNC machine tool according to the theoretical normal of the hole, thereby ensuring the verticality of the hole. At the same time, the outer diameter of the middle reverse hole drill sleeve 8 corresponds to the aperture of the final hole on the skeleton 1. The outer diameter of the replaceable drill sleeve 5 corresponds to the aperture of the curved surface drill jig 4, and the inner diameter of the replaceable drill sleeve 5 is determined according to the processing specifications of the relevant machine model and the tool specifications in the operation specifications, and the final hole aperture required by the drawing and the specifications is gradually increased on the basis of the initial hole; in addition, the outer diameter of different parts of the step pin 12 corresponds to the inner diameter of the reverse hole drill sleeve 8 and the inner diameter of the hole on the curved surface drill jig 4, thereby ensuring the accuracy during verification and the quality of the subsequent operation hole. Example 1

[0020] Reference Figure 1-Figure 3 , a technical solution proposed by the present invention: The main steps of replacing and assembling the aircraft curved skin 2 include: S1, remove the damaged skin 2 and reposition the new skin 2: remove the fasteners connecting the skeleton 1 and the damaged curved skin 2 and reposition the skeleton 1 and the new curved skin 2 according to the jig 3 tooling; S2, reverse hole initial hole: the reverse hole drill sleeve 8 is used to make the initial hole on the new skin 2 in the operable area on the jig 3 according to the final hole on the frame 1, and the temporary fastener 6 is installed to clamp the skin 2 and the frame 1; S3, hole expansion: on the basis of the initial holes made in the new skin 2, use a vertical drill and a step drill to expand all the initial holes, and install temporary fasteners 6 to clamp the skin 2 and the frame 1; S4, inspection: use the counter-hole drill sleeve 8, the step pin 12, the temporary fastener 6, etc. to locate the curved surface drilling jig 4 and verify the coaxiality and fix the curved surface drilling jig 4; S5, expanding and reaming the final hole: according to the curved surface drilling jig 4, use the replaceable drill sleeve 5 to expand and ream the final hole of the new skin 2 and remove burrs, install temporary fasteners 6 to clamp the skin 2 and the frame 1; S6, complete the hole making of skin 2: change the position of curved surface drilling jig 4, and press S4~S5 to complete the hole making operation of other areas of curved surface skin 2; S7, countersinking of skin 2: after decomposition and deburring, use positioning pins / temporary fasteners 6 to reposition the frame 1 and skin 2 on the jig 3 tooling and countersink and install the fasteners; S8. Complete the replacement and installation of the skin 2: Remove from the frame and press S2 to S6 to perform the final hole countersinking and installation of fasteners for the curved skin 2 in the remaining areas that cannot be operated on the jig 3.

[0021] Among them, the hole making process of the new curved surface skin 2 is the most critical in the replacement assembly processing steps of the curved surface skin 2. The following takes the process of replacing the new skin 2 of a certain model of cargo hold door frame product as an example to further illustrate the assembly processing method of the most critical hole making process of the present invention and the use method of the replacement assembly device, in which 6.35mm holes are made on the new skin 2 according to a row of 6.35mm final holes on a long beam of the skeleton 1.

[0022] Combined with Figure 1-8 The method for replacing the curved surface skin 2 of an aircraft comprises the following key steps: 1. After removing the damaged skin 2 and repositioning the frame 1 and the new skin 2 according to the jig 3, use the counter-drill sleeve 8 with an outer diameter of 6.35mm and an inner diameter of 2.5mm to make all the corresponding 2.5mm guide holes on the new skin 2 according to the 6.35mm final hole on the long stringer of the frame 1 and remove the burrs. Please refer to Figure 3 ; At the same time, use the 2.5mm spring pin 7 / pull code to clamp the skin 2 and the frame 1; 2. Remove the spring pin 7 / pull code, and on the basis of making 2.5mm guide holes in the new skin 2, use a 3.2mm vertical drill and a 2.5mm-3.2mm step knife to expand all 2.5mm guide holes to 3.2mm and remove burrs. Please refer to Figure 4 , and use 3.2mm spring pins 7 / pull codes to clamp the skin 2 and the frame 1; 3. Use a feeler gauge to check the gap between the skin 2 and the frame 1, and the gap between the curved drilling jig 4 and the skin 2. Install the counter-hole drill sleeve 8 on the long stringer of the frame 1, and insert the step pin 12 into the curved drilling jig 4 and pass it through the skin 2, the frame 1 and the counter-hole drill sleeve 8. Ensure that the drilling jig hole is coaxial with the long stringer hole of the frame 1. Use temporary fasteners 6 to fix the curved drilling jig 4. Please refer to Figure 6 ; 4. After verifying the coaxiality of the drill hole and the long stringer hole of the frame 1 again, check the fixation of the curved template and remove the counter-hole drill sleeve 8 and the stepped pin 12. Please refer to Figure 6 ,7; 5. Use the replaceable drill sleeve 5 to expand the new skin 2 to 4.0mm-4.6mm-6.2mm according to the drilling template. Finally, use the replaceable drill sleeve 5 to ream the new skin 2 to 6.35mm and deburr it. Install the 6.35mm temporary fastener 6 to clamp the skin 2 and the frame 1. Please refer to Figure 8 ; 6. Repeat steps 3-5 for the hole on the skin 2 corresponding to the long stringer to gradually expand the hole to 6.2mm, and finally ream the hole to 6.35 and deburr it. Install the temporary fastener 6 with a specification of 6.35mm to clamp the skin 2 and the frame 1; The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for replacing the curved surface skin of an aircraft, characterized in that: S1: removing the damaged skin (2) and repositioning the new skin (2), removing the fasteners connecting the frame (1) and the damaged curved surface skin (2), and repositioning the frame (1) and the new curved surface skin (2) according to the jig (3); S2: counter-drilling initial holes, using a counter-drilling sleeve (8) to drill initial holes on the new skin (2) in the operable area on the jig (3) according to the final holes on the frame (1), and installing temporary fasteners (6) to clamp the skin (2) and the frame (1); S3: Expanding holes, using a vertical drill and a step drill to expand all the initial holes on the basis of the initial holes made in the new skin (2), and installing temporary fasteners (6) to clamp the skin (2) and the frame (1); S4: Check, use the counter-hole drill sleeve (8), step pin (12), temporary fasteners (6), etc. to position the curved surface drilling jig (4) and verify the coaxiality and fix the curved surface drilling jig (4); S5: expanding and reaming the final hole, using a replaceable drill sleeve (5) according to the curved surface drilling template (4) to expand and ream the final hole of the new skin (2) and remove burrs, and installing temporary fasteners (6) to clamp the skin (2) and the frame (1); S6: completing the hole making of the skin (2), changing the position of the curved surface drilling jig (4), and completing the hole making operation of other areas of the curved surface skin (2) according to S4-S5; S7: countersinking the skin (2), disassembling and deburring, and then repositioning the frame (1) and the skin (2) on the jig (3) using positioning pins or temporary fasteners (6) to install fasteners; S8: After the replacement and installation of the skin (2) is completed, the frame is removed and the remaining areas on the jig (3) that cannot be operated are countersunk and fasteners are installed according to S2-S6.

2. The method for replacing the curved surface skin of an aircraft according to claim 1, characterized in that: In the above-mentioned S4, the gap between the skin (2) and the frame (1) and the gap between the curved surface drilling jig (4) and the skin (2) are checked using a feeler gauge, a reverse hole drilling sleeve (8) is installed on the long stringer of the frame (1), and a stepped pin (12) is inserted into the curved surface drilling jig (4) and passed through the skin (2) and the frame (1) and the reverse hole drilling sleeve (8), and the curved surface drilling jig (4) is fixed using a temporary fastener (6) while ensuring that the drilling jig hole is coaxial with the long stringer hole of the frame (1).

3. The method for replacing the curved surface skin of an aircraft according to claim 1, characterized in that: The inner diameter of the replaceable drill sleeve (5) is determined according to the tool specifications in the processing specifications and operation specifications of the relevant machine model, and the final hole diameter required by the drawing and specifications is gradually increased based on the initial hole.

4. The method for replacing the curved surface skin of an aircraft according to claim 1, characterized in that: The curved surface drilling jig (4) is obtained by establishing a curved surface drilling jig (4) model with a corresponding curvature in CATIA based on a three-dimensional model of the processed curved surface skin (2) and processing the model through a numerical control machine tool.

5. The method for replacing the curved surface skin of an aircraft according to claim 1, characterized in that: The normal direction of the drill sleeve hole on the curved surface drilling jig (4) is processed by a numerically controlled machine tool according to the theoretical normal direction of the hole to ensure the verticality of the hole.

6. A device for replacing an aircraft outer curved surface skin (2), characterized in that: The skin (2) replacement device comprises a curved surface drill jig (4), a reverse hole drill sleeve (8) and a replaceable drill sleeve (5); a side of the curved surface drill jig (4) close to the skin (2) is completely fitted with the skin (2); a drill sleeve hole is provided on the curved surface drill jig (4); the drill sleeve hole is perpendicular to the fitting surface of the curved surface drill jig (4) and the skin (2); the outer diameter of the reverse hole drill sleeve (8) is matched with the hole diameter of the terminal hole on the skeleton (1) part; and the outer diameter of the replaceable drill sleeve (5) is matched with the diameter of the drill sleeve hole.

7. The device for replacing the curved surface skin (2) of an aircraft according to claim 6, characterized in that: The number of the drill sleeve holes is at least 3, the drill sleeve holes are adjacent and symmetrically arranged, and the position spacing between the drill sleeve holes is consistent with the position spacing of the holes on the aircraft frame (1).

8. The device for replacing the curved surface skin (2) of an aircraft according to claim 7, characterized in that: The skin (2) replacement device also includes a stepped pin (12), the maximum diameter of the stepped pin (12) being adapted to the inner diameter of the drilling jig hole.

9. The device for replacing the curved surface skin (2) of an aircraft according to claim 8, characterized in that: The skin (2) replacement device also includes a temporary fastener (6), a spring pin (7) and a gasket (10), wherein the temporary fastener (6), the spring pin (7) and the gasket (10) are used to clamp the aircraft frame (1) and the skin (2).

10. The device for replacing the curved surface skin (2) of an aircraft according to claim 9, characterized in that: The replaceable drill sleeve (5) includes a plurality of different inner diameter specifications, so as to realize the step-by-step expansion of the hole of the curved surface skin (2).

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