An aircraft skin clamping device, a milling processing equipment and a processing method
By using aircraft skin clamping devices and vacuum adsorption technology, the problems of high cost and low efficiency of existing equipment have been solved, achieving efficient and precise skin milling, reducing costs and environmental pollution.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XIAN FUXING AVIATION TECHNOLOGY CO LTD
- Filing Date
- 2024-07-29
- Publication Date
- 2026-06-26
AI Technical Summary
Existing aircraft skin milling equipment is expensive and inefficient, easily leading to skin deformation and vibration, and the processing process is prone to environmental pollution.
An aircraft skin clamping device is adopted, including a fixture frame, skin support and vacuum clamping mechanism. The fixture surface is consistent with the skin shape for rigid support, and the reliable clamping and cleaning of the skin are ensured by vacuum adsorption and air blowing devices. It is then combined with a general gantry milling machine for processing.
It improves the efficiency and precision of aircraft skin milling, reduces processing costs, prevents skin deformation and vibration, and reduces environmental pollution.
Smart Images
Figure CN118720237B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of aircraft skin processing equipment, and more particularly to an aircraft skin clamping device. Furthermore, this application also relates to an aircraft skin milling processing equipment and an aircraft skin milling processing method. Background Technology
[0002] Aircraft skin refers to the shaped components that surround the aircraft's frame structure and are fixed to the frame with adhesives or rivets to form the aircraft's aerodynamic shape. The skin structure, formed by the aircraft skin and frame, has high load-bearing capacity and rigidity, yet is very lightweight, serving to bear and transmit aerodynamic loads. After bearing aerodynamic forces, the skin transmits these forces to the connected fuselage and wing frames, resulting in complex stress distribution. Furthermore, since the skin is in direct contact with the external environment, it requires not only high strength and good plasticity in the skin material, but also a smooth surface and high corrosion resistance.
[0003] Early or low-speed small aircraft used cloth (linen, cotton) as skin. At this stage, the skin could only withstand a limited portion of the aerodynamic load and did not participate in the overall stress distribution. Modern aircraft skins are mostly made of aluminum alloy, titanium alloy, or composite materials. The skin structure generally consists of an outer skin surface, an inner skin surface, a web, and holes. Aluminum alloy skins are typically made by stretching aluminum alloy material into a skin blank. The outer skin surface does not require processing, while the inner skin surface is drilled and milled to form the finished skin. Skin blanks are relatively thin, generally 3-6mm thick, and have a large single-piece area, poor rigidity, and are easily deformed during processing. High surface quality requirements and small wall thickness tolerances make processing very difficult, especially for hyperboloid skins.
[0004] Current milling processes for aircraft skins primarily employ mirror milling and chemical milling. Mirror milling requires specialized equipment, which supports and positions the outer skin surface corresponding to the milled area on the inner skin during the milling process. This not only results in expensive equipment but also a small support surface, making chattering a common occurrence. Chemical milling, on the other hand, is slow, leading to low efficiency and environmental pollution. Summary of the Invention
[0005] In order to improve the processing efficiency and quality of aircraft skin and reduce processing costs, this application provides an aircraft skin clamping device, milling equipment and processing method.
[0006] The aircraft skin clamping device provided in this application adopts the following technical solution:
[0007] An aircraft skin clamping device includes a jig frame, a skin support, and a vacuum clamping mechanism. The skin support is disposed on the jig frame, and a jig profile is formed on the side of the skin support opposite to the jig frame. The shape of the jig profile is consistent with the shape of the outer skin surface of the aircraft. A sealing groove is provided in the peripheral area of the jig profile. Multiple crisscrossing exhaust grooves are provided on the jig profile inside the sealing groove. The multiple exhaust grooves divide the jig profile into multiple skin support surfaces. The vacuum clamping mechanism includes a vent hole and a vacuum tube. The vent hole passes through the skin support and communicates with the exhaust grooves. The vacuum tube is connected to the vent hole and can be connected to an external vacuum source.
[0008] By adopting the above technical solution, a jig profile that matches the shape of the outer skin of the aircraft can form an integral rigid support for the aircraft skin, preventing deformation and vibration during processing. This allows for the use of general-purpose machining equipment to process the inner skin surface, ensuring the machining accuracy of the inner skin surface and improving the processing efficiency of the aircraft skin. Multiple crisscrossing exhaust grooves on the jig profile, along with vents connected to the exhaust grooves and vacuum tubes, create negative pressure within the exhaust grooves using an external vacuum source, adsorbing the entire aircraft skin onto the jig profile. This provides reliable clamping of the aircraft skin while simultaneously providing rigid support through multiple skin support surfaces, ensuring the machining accuracy of the inner skin surface. Sealing grooves in the peripheral area of the jig profile, after installing sealing strips, maintain the vacuum level between the jig profile and the aircraft skin, increasing the clamping force of the aircraft skin on the jig profile.
[0009] In one specific implementation, the fixture surface inside the sealing groove includes multiple independent adsorption blocks, the exhaust grooves in each adsorption block are interconnected, the exhaust grooves between different adsorption blocks are isolated from each other, each adsorption block is provided with at least one vent hole, the vacuum clamping mechanism also includes an air valve, and the vent hole in each adsorption block is connected to the vacuum tube through the air valve.
[0010] By adopting the above technical solution, multiple independent adsorption blocks set on the jig surface can form multiple independent adsorption areas, creating independent clamping forces on different parts of the aircraft skin. This helps ensure reliable clamping of the aircraft skin on the skin support. By utilizing the vent holes in each adsorption block connected to vacuum tubes via air valves, the negative pressure formation within each adsorption block can be controlled independently, allowing for independent control and adjustment of the clamping conditions of different parts of the aircraft skin.
[0011] In one specific implementation, the vacuum clamping mechanism further includes a dust separator disposed between the vent and the air valve.
[0012] By adopting the above technical solution, the dust separator installed between the vent and the valve can isolate the processing dust and debris entering the vacuum clamping mechanism, preventing the dust and debris from affecting the normal operation of the vacuum clamping mechanism.
[0013] In one specific implementation, the dust collector includes a dust-proof cylinder, a dust-proof air inlet pipe, a dust-proof baffle ring, and a dust-proof air outlet pipe. The dust-proof cylinder is a sealed hollow cylinder. The dust-proof air inlet pipe is fixed to the top of the dust-proof cylinder and extends through the top surface of the dust-proof cylinder to the bottom area of the dust-proof cylinder. Multiple dust-proof baffle rings are provided, with their free ends inclined downwards and respectively disposed on the inner wall of the dust-proof cylinder or the outer wall of the dust-proof air inlet pipe. The dust-proof air outlet pipe is fixed to the upper part of the dust-proof cylinder and opens through the side wall of the dust-proof cylinder above the dust-proof baffle ring.
[0014] By adopting the above technical solution, the dust-proof inlet pipe extends to the bottom area of the dust-proof cylinder, and the dust-proof outlet pipe is located at the top of the dust-proof cylinder. This creates an upward airflow inside the dust-proof cylinder, utilizing the gravity of the processing dust and debris to prevent larger diameter dust and debris from flowing into the dust-proof outlet pipe, thus reducing the amount of dust and debris entering the dust-proof outlet pipe. The design ensures the rotational accuracy of the rotating mounting table and prevents safety risks from exposed gears. Multiple downward-sloping dust-proof baffles on the inner wall of the dust-proof cylinder or the outer wall of the dust-proof inlet pipe obstruct the upward airflow from the bottom of the dust-proof cylinder, creating a localized downward airflow. This promotes the detachment of dust and debris mixed in the airflow by inertia, causing them to settle at the bottom of the dust-proof cylinder.
[0015] In one specific implementation, the bottom wall of the sealing groove is provided with a sealing strip adsorption hole, which passes through the skin support and is connected to the vacuum tube.
[0016] By adopting the above technical solution, the sealing strip adsorption holes set on the bottom wall of the sealing groove can be used to stably adsorb the sealing strip in the sealing groove using an external vacuum source, ensuring the positional stability of the sealing strip in the sealing groove and ensuring a reliable seal between the sealing strip and the skin support and the aircraft skin.
[0017] In one specific implementation, the aircraft skin clamping device of this application further includes an air blowing device, wherein an air blowing hole is provided on the skin support surface, and the air blowing hole passes through the skin support and is connected to the air blowing device.
[0018] By adopting the above technical solution, air holes set on the skin support surface can be used to briefly blow air into the surface when there are debris or debris on the skin support surface that affect the reliable adsorption of the aircraft skin. The debris or debris is blown into the exhaust groove and then removed by the vacuum clamping mechanism, ensuring reliable adsorption of all parts of the aircraft skin.
[0019] The aircraft skin milling equipment provided in this application adopts the following technical solution:
[0020] An aircraft skin milling machine includes a gantry milling machine and the aircraft skin clamping device of this application. The aircraft skin clamping device is disposed below the gantry of the gantry milling machine so that the inner skin surface of the aircraft skin clamped on the aircraft skin clamping device can be milled using the gantry milling machine.
[0021] By adopting the above technical solution, the aircraft skin clamping device of this application can simultaneously form a reliable clamping force on the aircraft skin using vacuum suction force, and provide rigid support to the outer skin surface. This allows for milling of the inner skin surface using a general-purpose gantry milling machine, preventing deformation of the aircraft skin caused by the milling force exerted by the milling cutter on the machined surface. Furthermore, the aircraft skin clamping device of this application can achieve large-area close contact with the aircraft skin through a fixture profile that matches the shape of the outer skin surface, preventing vibration of the aircraft skin during milling of the inner skin surface and improving the machining accuracy of aircraft skin milling.
[0022] The aircraft skin milling method provided in this application adopts the following technical solution:
[0023] An aircraft skin milling method, using the aircraft skin milling processing equipment of this application, includes the following steps: S10, milling the fixture profile so that the shape of the fixture profile is consistent with the shape of the outer skin surface of the aircraft skin; S20, installing a sealing strip in the sealing groove, placing the aircraft skin on the fixture profile so that the periphery of the outer skin surface of the aircraft skin contacts the sealing strip; S30, activating the vacuum clamping mechanism to adsorb the outer skin surface of the aircraft skin onto the fixture profile; S40, activating the gantry milling machine to mill the inner skin surface of the aircraft skin.
[0024] By adopting the above technical solutions, milling the fixture surface ensures the consistency between the fixture surface shape and the aircraft skin outer surface shape, guaranteeing a large-area close contact between the fixture surface and the aircraft skin, and providing reliable rigid support for the aircraft skin. This prevents deformation and vibration of the aircraft skin caused by milling, ensuring the machining accuracy of the aircraft skin. The vacuum clamping mechanism uses the exhaust groove to adhere to the aircraft skin surface, creating a large-area clamping force perpendicular to the outer skin surface, reducing deformation caused by clamping force. Furthermore, the contact between the outer skin surface periphery and the sealing strip creates a large vacuum area between the aircraft skin periphery and the fixture surface, generating greater adsorption force over a larger area, ensuring the reliability of the aircraft skin clamping.
[0025] In one specific implementation scheme, before step S30, the method further includes step S25: detecting the shape state of the aircraft skin; after step S30, the method further includes step S35: detecting the adsorption status of the aircraft skin, and intermittently activating the air blowing device corresponding to the skin support surface of the unadhesive part.
[0026] By adopting the above technical solution and utilizing the detection data of the aircraft skin's shape, the fit between the outer skin surface and the fixture surface can be accurately determined by detecting the aircraft skin clamped on the skin support. By detecting the adhesion of the aircraft skin, areas where the aircraft skin is not tightly adhered to the skin support can be detected in a timely manner. When an area where the aircraft skin and the skin support are not tightly adhered is found, an air blowing device corresponding to the skin support surface of the area where the skin is not tightly adhered is activated. Gas is blown out through the air blowing hole, and the airflow flowing from the air blowing hole to the exhaust groove under the aircraft skin blows the debris and debris trapped between the outer skin surface and the fixture surface into the exhaust groove, ensuring that the outer skin surface and the fixture surface can be completely adhered.
[0027] In one specific implementation scheme, step S40 includes the following steps: S41, rough milling the aircraft skin from the middle to both sides according to the detected shape of the aircraft skin; S42, measuring the wall thickness of each processed area of the aircraft skin; S43, setting the tool compensation value for each processed area of the aircraft skin according to the measurement results; S44, performing finish milling on each processed area of the aircraft skin according to the tool compensation value.
[0028] By adopting the above technical solution and using a rough milling method on the aircraft skin from the middle to both sides, movement of the aircraft skin during rough milling can be prevented, ensuring the rough milling accuracy of the aircraft skin. By measuring the wall thickness of each machining area and setting the tool compensation value, the impact of fixture surface machining errors and aircraft skin rough machining errors on machining accuracy can be reduced, thereby improving the final machining accuracy of the aircraft skin.
[0029] In summary, this application includes at least one of the following beneficial technical effects:
[0030] 1. By milling the fixture profile, the consistency between the fixture profile shape and the outer skin surface shape of the aircraft can be ensured, allowing for a larger area and tighter fit between the outer skin surface and the fixture profile. The fixture profile provides rigid support to the outer skin surface and improves the clamping force and stability of the aircraft skin on the skin support. This enables the use of general-purpose milling machines to mill the inner skin surface, reducing deformation and vibration of the aircraft skin during milling and improving the milling efficiency and accuracy of the aircraft skin.
[0031] 2. By utilizing multiple crisscrossing exhaust channels on the jig surface, negative pressure can be guided to a wider range on the jig surface, forming a uniform adsorption force on the aircraft skin over a larger area. This ensures that different parts of the aircraft skin can be reliably clamped onto the skin support, improving the reliability and stability of the aircraft skin clamping and preventing excessive adsorption force in local areas of the aircraft skin, thus reducing clamping deformation of the aircraft skin.
[0032] 3. By setting multiple adsorption areas on the jig surface and setting gas valves between each adsorption area and the vacuum tube, the adsorption status and adsorption force of different parts of the aircraft skin can be controlled separately, thereby ensuring that different parts of the aircraft skin can be reliably adsorbed on the skin support, ensuring the reliability and stability of the aircraft skin clamping.
[0033] 4. By providing air blowing holes on each skin support surface, a short airflow can be blown between the aircraft skin and the fixture surface through the air blowing holes, blowing the debris and debris trapped between the aircraft skin and the fixture surface into the exhaust groove. This allows for the removal of debris and debris trapped between the aircraft skin and the fixture surface without removing the aircraft skin, ensuring that different parts of the aircraft skin can be reliably adsorbed onto the fixture surface, forming a tight fit between the outer skin surface and the fixture surface, ensuring reliable clamping of the aircraft skin and improving the machining accuracy of the aircraft skin. Attached Figure Description
[0034] Figure 1 This is a schematic diagram of one embodiment of the aircraft skin clamping device of this application.
[0035] Figure 2 This is a rear view of one embodiment of the aircraft skin clamping device of this application.
[0036] Figure 3 This is a schematic diagram of an embodiment of the aircraft skin clamping device of this application after clamping the aircraft skin.
[0037] Figure 4 This is a schematic diagram of the vacuum clamping mechanism in one embodiment of the aircraft skin clamping device of this application.
[0038] Figure 5 This is a cross-sectional schematic diagram of one embodiment of the aircraft skin clamping device of this application.
[0039] Figure 6 This is a schematic diagram of a dust separator in one embodiment of the aircraft skin clamping device of this application.
[0040] Figure 7 This is a flowchart of one embodiment of the aircraft skin milling method of this application.
[0041] Figure 8 This is a flowchart illustrating the aircraft skin milling process in one embodiment of the aircraft skin milling method of this application.
[0042] Explanation of reference numerals in the attached drawings: 1. Fixture frame; 2. Skin support; 21. Fixture profile; 211. Skin support surface; 212. Adsorption block; 213. Air blowing hole; 22. Sealing groove; 221. Sealing strip adsorption hole; 23. Exhaust groove; 3. Vacuum clamping mechanism; 31. Vent hole; 32. Vacuum tube; 33. Air valve; 34. Dust separator; 341. Dust separator cylinder; 342. Dust separator air inlet pipe; 343. Dust separator retaining ring; 344. Dust separator air outlet pipe; 345. Dust outlet; 4. Air blowing device; 5. Aircraft skin; 6. Skin pressure plate. Detailed Implementation
[0043] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this application.
[0044] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0045] One embodiment of the aircraft skin clamping device of this application, such as Figures 1 to 5 As shown, the system includes a fixture frame 1, a skin support 2, and a vacuum clamping mechanism 3. The fixture frame 1 is a structure that can be fixed to the ground or a worktable in the processing area for fixing and positioning the skin support 2. The skin support 2 is positioned above the fixture frame 1 for clamping and supporting the aircraft skin 5. The skin support 2 and the fixture frame 1 can be independently machined and then installed together, or they can be integrally formed. Typically, the fixture frame 1 and the skin support 2 are integrally formed components made of cast aluminum. Using cast aluminum components reduces the weight and machining workload of the clamping device, and also offers relatively low material costs. Furthermore, since the aircraft skin 5 is made of aluminum alloy, the skin support 2 is also made of aluminum alloy, ensuring that its hardness is not higher than that of the aircraft skin 5. This prevents the aircraft skin 5 from being scratched or crushed by the high-hardness material of the skin support 2 when clamped onto it, thus providing a certain degree of protection for the aircraft skin 5.
[0046] The side of the skin support 2 opposite to the fixture frame 1 is designated as a fixture surface 21, which is typically formed by milling on cast aluminum. The shape and size of the fixture surface 21 are machined to match the shape and size of the outer skin surface of the aircraft skin 5, i.e., the clamping surface of the aircraft skin 5. In this embodiment, after the fixture surface 21 is installed on the machining station, it is milled by the machining equipment used to process the aircraft skin 5, which better ensures the consistency between the fixture surface 21 and the outer skin surface of the aircraft skin 5.
[0047] A sealing groove 22 is provided in the peripheral area of the fixture surface 21. The sealing groove 22 is usually configured such that when the aircraft skin 5 is placed on the clamping part of the fixture surface 21, the edge of the aircraft skin 5 can completely cover the sealing groove 22. In this way, the sealing strip installed in the sealing groove 22 can form an isolation between the inner and outer parts of the sealing groove 22. A sealed space is formed between the aircraft skin 5 and the fixture surface 21 on the inner side of the sealing groove 22, which is conducive to the formation of a vacuum environment in the sealed space.
[0048] Multiple venting grooves 23 are provided on the fixture surface 21 inside the sealing groove 22. The multiple venting grooves 23 are arranged longitudinally and transversely along the length and width directions of the skin support 2 on the fixture surface 21. The multiple longitudinally and transversely arranged venting grooves 23 separate and surround multiple mutually isolated skin support surfaces 211 on the fixture surface 21. After the aircraft skin 5 is clamped onto the skin support 2, the multiple skin support surfaces 211 support the outer skin surface of the aircraft skin 5, forming a rigid support for the aircraft skin 5. The width of the venting grooves 23 is small, usually smaller than the diameter of the milling cutter of the machining equipment. While ensuring the transmission of negative pressure, it also ensures that the aircraft skin 5 will not undergo large deformation when the milling cutter performs milling machining on the venting grooves 23.
[0049] The vacuum clamping mechanism 3 includes a vent 31 and a vacuum tube 32. The vent 31 can be a hole machined into the skin support 2 or into other solid structures. The vent 31 passes through the skin support 2 and connects to the exhaust groove 23, typically extending downwards from the bottom of the exhaust groove 23, passing through the opening of the skin support 2, and connecting to the other side of the skin support 2. One end of the vacuum tube 32 is fixed to the wall of the vent 31 and connects to the vent 31; the other end is used to connect to an external vacuum source. The external vacuum source can be a vacuum pump specifically designed for the aircraft skin clamping device of this application, or a vacuum pumping device or vacuum container shared with other equipment.
[0050] The fixture surface 21 may also be provided with positioning protrusions corresponding to the process holes on the aircraft skin 5. When the aircraft skin 5 is clamped on the fixture surface 21, the positioning protrusions are located in the corresponding process holes on the aircraft skin 5, ensuring the positioning accuracy of the aircraft skin 5 on the fixture surface 21.
[0051] Multiple skin pressure plates 6 are also provided on the outer side of the sealing groove 22 on the jig surface 21. The skin pressure plates 6 are fixed to the jig surface 21 by bolts. When the aircraft skin 5 is clamped on the jig surface 21, the skin pressure plates 6 can also press on the edge of the aircraft skin 5 to form an auxiliary clamping of the aircraft skin 5, further enhancing the reliability of the aircraft skin 5 clamping.
[0052] In some embodiments of the aircraft skin clamping device of this application, such as Figures 1 to 4 As shown, the fixture surface 21 inside the sealing groove 22 is configured as nine independent adsorption blocks 212. Multiple exhaust channels 23 are respectively disposed within each adsorption block 212 and are interconnected within each adsorption block 212 to form a unified, interconnected exhaust channel network. However, the exhaust channels 23 are not connected between different adsorption blocks 212, thus isolating the exhaust channel networks of different adsorption blocks 212 from each other.
[0053] At least one vent 31 is provided in each adsorption block 212. The vent 31 can be located on any one of the exhaust channels 23 or at the intersection of two exhaust channels 23. Below the skin support 2, an air valve 33 is provided at the outlet of the vent 31. One end of the air valve 33 is connected to and communicates with the vent 31, and the other end is connected to the vacuum tube 32. Each air valve 33 can control whether a negative pressure is formed in the exhaust channel 23 within an adsorption block 212, thereby enabling vacuum clamping of the aircraft skin 5 on each adsorption block 212 independently. By simultaneously vacuum clamping the aircraft skin 5 within nine adsorption blocks 212, a reliable overall clamping of the aircraft skin 5 can be achieved. Even if debris or fragments appear on the skin support surface 211 within a certain adsorption block 212, or if the sealing strip fails to seal properly, resulting in poor adsorption of the aircraft skin 5, the effective adsorption of other adsorption blocks 212 can ensure the overall clamping stability of the aircraft skin 5. This prevents poor adsorption in local areas from affecting the overall adsorption state of the aircraft skin 5 and causing clamping failure of the aircraft skin 5.
[0054] In a preferred embodiment of the aircraft skin clamping device of this application, such as Figure 4 and Figure 5 As shown, a dust separator 34 is also installed on the negative pressure pipeline of the vacuum clamping mechanism 3. The dust separator 34 can be any mechanism that can isolate or remove dust and debris in the negative pressure pipeline, such as a filter screen or dust bag. The dust separator 34 is usually installed between the vent 31 and the air valve 33 to isolate and remove processing dust and processing debris mixed into the negative pressure air path, and to ensure the normal operation of the air valve 33 and the external vacuum source.
[0055] As one specific embodiment of the aircraft skin clamping device of this application, such as Figure 6 As shown, the dust collector 34 includes a dust collection cylinder 341, a dust collection inlet pipe 342, a dust collection baffle ring 343, and a dust collection outlet pipe 344. The dust collection cylinder 341 is typically a hollow cylinder with closed ends. The upper part of the dust collection cylinder 341 is cylindrical, and the lower part is an inverted frustum shape. The bottom of the dust collection cylinder 341 is provided with an openable dust discharge port, through which the dust and debris collected inside the dust collection cylinder 341 can be discharged.
[0056] A dust-proof air inlet pipe 342 is fixedly installed at the top of the dust-proof cylinder 341, extending through the top wall of the dust-proof cylinder 341 to the bottom area of the dust-proof cylinder 341. The upper end of the dust-proof air inlet pipe 342 is connected to the wall of the vent 31, and is used to introduce airflow from the vent 31 into the bottom area of the dust-proof cylinder 341. A dust-proof baffle ring 343 is installed inside the dust-proof cylinder 341, and multiple dust-proof baffle rings 343 are provided inside the dust-proof cylinder 341.
[0057] Specifically, two dust-proof baffle rings 343 are provided on the inner wall of the dust-proof cylinder 341, and one dust-proof baffle ring 343 is provided on the outer side of the dust-proof air inlet pipe 342. The outer edge of the dust-proof baffle ring 343 provided on the dust-proof cylinder 341 is fixed to the dust-proof cylinder 341, and the inner edge extends obliquely downward toward the dust-proof air inlet pipe 342; the inner edge of the dust-proof baffle ring 343 fixed on the dust-proof air inlet pipe 342 is fixed to the dust-proof air inlet pipe 342, and the outer edge extends obliquely downward toward the dust-proof cylinder 341. The dust-proof baffle ring 343 on the dust-proof air inlet pipe 342 is positioned between the dust-proof baffle rings 343 on the two dust-proof cylinders 341, and the outer diameter of the former is larger than that of the latter. This causes the airflow flowing upward from the bottom of the dust-proof cylinder 341 to have multiple downward flow tendencies due to the obstruction of multiple dust-proof baffle rings 343. This is beneficial for the dust and debris mixed in the airflow to fall from the gentle upward flow when the airflow turns, and to separate from the airflow and fall to the bottom of the dust-proof cylinder 341.
[0058] The dust-proof exhaust pipe 344 is fixed to the upper side wall of the dust-proof cylinder 341. One end of the dust-proof exhaust pipe 344 passes through the side wall of the dust-proof cylinder 341, and the opening of the dust-proof exhaust pipe 344 is located above the dust-proof baffle ring 343 on the upper part of the dust-proof cylinder 341 and is located near the wall of the dust-proof cylinder 341. The other end of the dust-proof exhaust pipe 344 is connected to the air valve 33, which is used to draw away the negative pressure airflow after removing dust and debris through the vacuum tube 32.
[0059] In some embodiments of the aircraft skin clamping device of this application, such as Figure 1 As shown, sealing strip adsorption holes 221 are provided on the bottom wall of the sealing groove 22. The sealing strip adsorption holes 221 are distributed within each sealing groove 22, and each sealing strip adsorption hole 221 opens through the skin support 2 at its lower part and is connected to the vacuum tube 32 via a pipe. The sealing strip adsorption holes 221 reliably adsorb the sealing strip installed in the sealing groove 22, ensuring the stability of the sealing strip's position and preventing displacement of the sealing strip under external force, which could lead to poor sealing.
[0060] In some embodiments of the aircraft skin clamping device of this application, such as Figure 1 and Figure 2 As shown, each skin support surface 211 on the fixture profile 21 has an air blowing hole 213 in the middle. The air blowing hole 213 passes through the skin support 2 and opens into the bottom surface of the skin support 2, and is connected to the air blowing device 4 located below the skin support 2. The air blowing device 4 can be an air pump located below the skin support 2, or it can be an air supply pipe connected to an external air compressor or a high-pressure air tank.
[0061] An air blowing device 4 can be installed below each air blowing hole 213, or an air blowing device 4 can be installed below multiple air blowing holes 213 in an adjacent area. Multiple air blowing holes 213 in an area can be connected to an air blowing device 4 through an air blowing pipe.
[0062] One embodiment of the aircraft skin milling equipment of this application includes a general-purpose gantry milling machine and an aircraft skin clamping device according to any embodiment of this application. The aircraft skin clamping device is fixed on the ground below the gantry of the gantry milling machine and is used to clamp the aircraft skin 5 to be processed onto the aircraft skin clamping device. The gantry milling machine typically uses a five-axis linkage gantry milling machine to control the five-axis linkage action of the milling cutter to mill the inner skin surface of the aircraft skin 5. Since the aircraft skin clamping device of this application reliably vacuum clamps the aircraft skin 5 and uses the fixture profile 21 to form a hard support for the outer skin surface of the aircraft skin 5, it can prevent the aircraft skin 5 from moving and deforming during the processing. This not only enables the processing of the aircraft skin 5 using a general-purpose machining tool, reducing processing costs, but also prevents vibration during the processing of the aircraft skin 5, improving the processing quality of the aircraft skin 5.
[0063] When processing an aircraft skin 5, the inventor used a traditional mirror milling machine, which took about 26 hours to complete the processing of one aircraft skin 5. However, after using the aircraft skin milling processing equipment of this application, and using the aircraft skin clamping device of this application to clamp the aircraft skin 5, and using a five-axis linkage gantry milling machine to process it, the processing of the same aircraft skin 5 took about 22 hours, which improved the processing efficiency by about 15%.
[0064] One embodiment of the aircraft skin milling method of this application uses the aircraft skin milling processing equipment of any embodiment of this application for processing, such as... Figure 7 As shown, it includes the following steps:
[0065] S10, Milling fixture profile 21:
[0066] The aircraft skin clamping device of this application is fixed on the ground below the gantry of the gantry milling machine using the fixture frame 1. The gantry milling machine is started to mill the fixture surface 21 on the skin support 2. The machining parameters are set according to the technical parameters provided by the customer, and the shape of the fixture surface 21 is machined to be consistent with the shape of the outer skin surface of the aircraft skin 5.
[0067] Since the machining of the jig surface 21 is performed after the aircraft skin clamping device of this application is installed and fixed, the installation error of the clamping device is reduced. After milling, the surface roughness of the jig surface 21 can reach Ra1.6, and the contour accuracy is within ±0.1mm. This ensures that the outer skin surface of the aircraft skin 5 is in close contact with the jig surface 21, ensuring the reliability of the aircraft skin 5 clamping on the skin support 2.
[0068] Positioning protrusions corresponding to the process holes on the aircraft skin 5 can also be machined on the fixture surface 21, thereby enabling the positioning protrusions to define the position of the aircraft skin 5.
[0069] S20, Placement and positioning of aircraft skin 5 on skin support 2:
[0070] A sealing strip is installed in the sealing groove 22, and the aircraft skin is placed on the fixture surface 21 so that the process holes on the aircraft skin 5 are fitted onto the positioning protrusions on the fixture surface 21, ensuring the positioning accuracy of the aircraft skin 5 and preventing the aircraft skin 5 from moving during the processing.
[0071] After the aircraft skin 5 is placed on the fixture surface 21, the peripheral part of the aircraft skin 5 is located on the sealing strip, so that the outer skin surface is in contact with the sealing strip, forming a seal between the sealing strip and the fixture surface 21 and the outer skin surface. This allows a space isolated from the outside world to be formed inside the sealing strip between the aircraft skin 5 and the skin support 2. The vacuum clamping mechanism can better create a vacuum state in this isolated space and use the external atmospheric pressure to clamp the aircraft skin 5 onto the skin support 2.
[0072] S30, clamping of aircraft skin 5:
[0073] The vacuum clamping mechanism 3 is activated. Specifically, when using a vacuum pump as the vacuum source, the vacuum pump is activated; when using a shared vacuum pumping device or vacuum container as the vacuum source, the air valve located on the negative pressure passage is opened, creating a vacuum negative pressure in the remaining isolation space between the exhaust groove 23 and the aircraft skin 5 and the skin support 2. The air pressure difference on both sides of the aircraft skin 5 is used to tightly adhere the aircraft skin 5 to the fixture surface 21, achieving the effect of clamping the aircraft skin 5 onto the fixture surface 21. After clamping, the outer skin surface of the aircraft skin 5 is tightly attached to the skin support surface 211, which forms a rigid support under the aircraft skin 5. The exhaust groove 23 is usually small in width. On the one hand, the elasticity of the aircraft skin 5 itself can form support within a small range; on the other hand, a milling cutter with a diameter larger than the width of the exhaust groove 23 can be used to prevent the milling force from acting entirely within the width range of the exhaust groove 23.
[0074] S40. Milling is performed on the aircraft skin 5:
[0075] The gantry milling machine is started, and the inner skin surface of the aircraft skin 5 is milled according to the machining requirements. Since the shape of the fixture surface 21 is consistent with the shape of the outer skin surface of the aircraft skin 5, the aircraft skin 5 does not undergo local deformation when it is clamped on the clamping fixture by vacuum adsorption. This makes the machined shape of the inner skin surface of the aircraft skin 5 close to the actual shape of the inner skin surface in its natural state, which is beneficial to improving the machining accuracy of the inner skin surface.
[0076] In some embodiments of the aircraft skin milling method of this application, such as Figure 7 As shown, before step S30, step S25 is also set to detect the shape and condition of the aircraft skin:
[0077] After the aircraft skin 5 is placed on the skin support 2, the state of the aircraft skin 5 blank is detected by a blue light scanner. Information such as the shape and thickness of the blank is recorded, and the differences between the blank's shape and design requirements (deformation) and the differences between the thickness of different parts of the blank and machining requirements (machining allowance) are calculated. This is beneficial for setting machining process parameters such as the feed rate of the milling equipment when milling the inner skin surface.
[0078] Following step S30, step S35 is also included to inspect and address any abnormal adhesion on the aircraft skin 5:
[0079] The adsorption status of different parts of the aircraft skin 5 is tested. The specific testing method can be to tap the surface of the inner skin, or to use a blue light scanner to detect the shape of the aircraft skin 5 and compare it with the detection value before adsorption. This can help to find out whether there are areas of the aircraft skin 5 that have not been effectively adsorbed onto the fixture surface 21.
[0080] If areas where adhesion is not effectively maintained are found, after ruling out poor sealing of the sealing strip, the problem is usually due to debris or fragments between the aircraft skin 5 and the skin support surface 211. If the sealing strip is faulty, it can be replaced. For debris or fragments between the aircraft skin 5 and the skin support surface 211, the air blowing device 4 corresponding to the area of the skin support surface 211 that is not properly adhered can be activated intermittently. High-pressure gas is blown in through the air blowing hole 213, causing a localized lifting of the aircraft skin 5. The flow of high-pressure gas towards the exhaust groove 23 flushes the debris or fragments into the exhaust groove 23, where they are then discharged by the vacuum clamping mechanism 3. After the air blowing device 4 is turned off, the vacuum clamping mechanism 3 can effectively adhere the aircraft skin 5 to the skin support surface 211 using negative pressure, thus eliminating the problem of poor adhesion of the aircraft skin 5 without removing it.
[0081] In a preferred embodiment of the aircraft skin milling method of this application, such as Figure 8 As shown, step S40 includes the following steps:
[0082] S41. Based on the inspected shape of the aircraft skin 5, rough milling is performed on the aircraft skin. Rough milling is carried out from the middle of the web of the aircraft skin 5 outwards. Specifically, web grooves of different wall thicknesses are milled sequentially, with each web groove using a reciprocating milling method, ensuring that the remaining thickness after cutting is greater than 1mm. Milling is performed using a five-axis linkage system, which reduces machining deformation of the aircraft skin 5 and improves machining efficiency.
[0083] S42. Measure the wall thickness of each machined area of the aircraft skin. After rough milling, use an ultrasonic vibrator to measure the wall thickness of each area and record the measured thickness value as the basis for setting parameters for subsequent finish milling.
[0084] S43. Based on the measurement results and the design requirements of the aircraft skin 5, determine the tool compensation value for each machining area of the aircraft skin 5.
[0085] S44. Input the tool offset values of different parts of the aircraft skin 5 into the milling machine tool, and perform finish milling on each machining area of the aircraft skin 5 according to the tool offset values. In this way, the thickness tolerance of each machining area can be controlled within ±0.1mm.
[0086] In the description of this application, the references to terms such as "an embodiment," "specific embodiment," and "preferred embodiment" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0087] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. An aircraft skin clamping device, characterized in that, The system includes a jig frame (1), a skin support (2), a vacuum clamping mechanism (3), and an air blowing device (4). The skin support (2) is mounted on the jig frame (1). The side of the skin support (2) opposite to the jig frame (1) is set as a jig surface (21). The shape of the jig surface (21) is consistent with the shape of the outer skin surface of the aircraft. A sealing groove (22) is provided in the peripheral area of the jig surface (21). Multiple intersecting exhaust grooves (23) are provided on the jig surface (21) inside the sealing groove (22). The exhaust groove (23) divides multiple skin support surfaces (211) on the jig profile (21). The vacuum clamping mechanism (3) includes a vent hole (31) and a vacuum tube (32). The vent hole (31) passes through the skin support (2) and is connected to the exhaust groove (23). The vacuum tube (32) is connected to the vent hole (31) and can be connected to an external vacuum source. An air blowing hole (213) is provided on the skin support surface (211). The air blowing hole (213) passes through the skin support (2) and is connected to the air blowing device (4).
2. The aircraft skin clamping device according to claim 1, characterized in that, The fixture surface (21) inside the sealing groove (22) includes multiple independent adsorption blocks (212). The exhaust grooves (23) in each adsorption block (212) are interconnected. The exhaust grooves (23) between different adsorption blocks (212) are isolated from each other. Each adsorption block (212) is provided with at least one ventilation hole (31). The vacuum clamping mechanism (3) also includes an air valve (33). The ventilation hole (31) in each adsorption block (212) is connected to the vacuum tube (32) through the air valve (33).
3. The aircraft skin clamping device according to claim 2, characterized in that, The vacuum clamping mechanism (3) also includes a dust separator (34), which is disposed between the vent (31) and the air valve (33).
4. The aircraft skin clamping device according to claim 3, characterized in that, The dust collector (34) includes a dust collector cylinder (341), a dust collector inlet pipe (342), a dust collector baffle ring (343), and a dust collector outlet pipe (344). The dust collector cylinder (341) is a sealed hollow cylinder. The dust collector inlet pipe (342) is fixed to the top of the dust collector cylinder (341) and extends through the top surface of the dust collector cylinder (341) to the bottom area of the dust collector cylinder (341). Multiple dust collector baffle rings (343) are provided, and their free ends are inclined downwards and respectively provided on the inner wall of the dust collector cylinder (341) or the outer wall of the dust collector inlet pipe (342). The dust collector outlet pipe (344) is fixed to the upper part of the dust collector cylinder (341) and opens through the side wall of the dust collector cylinder (341) above the dust collector baffle ring (343).
5. The aircraft skin clamping device according to claim 1, characterized in that, The bottom wall of the sealing groove (22) is provided with a sealing strip adsorption hole (221), which passes through the skin support (2) and is connected to the vacuum tube (32).
6. An aircraft skin milling machine, characterized in that, The invention includes a gantry milling machine and an aircraft skin clamping device according to any one of claims 1-5, wherein the aircraft skin clamping device is disposed below the gantry of the gantry milling machine to enable the gantry milling machine to mill the inner skin surface of the aircraft skin clamped on the aircraft skin clamping device.
7. A method for milling aircraft skin, using the aircraft skin milling equipment according to claim 6, characterized in that, Includes the following steps: S10. Mill the fixture profile (21) so that the shape of the fixture profile (21) is consistent with the shape of the outer skin surface of the aircraft skin; S20. Install a sealing strip in the sealing groove (22), place the aircraft skin on the jig profile (21), so that the periphery of the outer skin surface of the aircraft skin contacts the sealing strip; S30. Start the vacuum clamping mechanism (3) to adsorb the outer skin surface of the aircraft skin onto the jig surface (21); S40. Start the gantry milling machine and perform milling on the inner skin surface of the aircraft skin.
8. The method according to claim 7, characterized in that, Before step S30, the following steps are also included: S25. Detect the shape and condition of the aircraft skin; Following step S30, the following step is also included: S35. Detect the adsorption status of the aircraft skin and periodically activate the air blowing device (4) corresponding to the skin support surface (211) of the unadsorbed part.
9. The method according to claim 8, characterized in that, Step S40 includes the following steps: S41. Based on the detected shape of the aircraft skin, perform rough milling on the aircraft skin from the middle to both sides. S42. Measure the wall thickness of each processed area of the aircraft skin; S43. Based on the measurement results, set the tool compensation value for each machining area of the aircraft skin; S44. Perform precision milling on each machining area of the aircraft skin according to the tool compensation value.