Universal clamp for drilling holes in vacuum clamping area of aircraft composite floor

Abstract

The invention relates to a universal fixture for drilling holes in a vacuum clamping area of an aircraft composite floor, which comprises a vacuum adsorption platform, a welding base, an air exhaust system for connecting a vacuum pump, a workpiece, an air leakage delaying mechanism and a sealing ring, an air exhaust groove and an air exhaust hole used for being communicated with the air exhaust system are formed in the upper portion of the vacuum adsorption platform, the air exhaust system is arranged in the welding base, the sealing ring is pressed into the air exhaust groove, the air leakage delaying mechanism is laid on the sealing ring, and a workpiece is placed on the air leakage delaying mechanism. The vacuum degree required in a non-sealing state can be kept, so that the stability of vacuum clamping force in the cutting machining process is ensured, the technological requirement that a large-diameter through hole cannot be drilled in a vacuum clamping area is broken through, the labor intensity of workers is greatly relieved, and the production efficiency is improved; the device is suitable for drilling and milling peripheral contours of aircraft composite floor parts of different specifications and sizes, and is high in universality.

Description

Technical Field

[0001] The invention relates to the technical field of composite material machining, in particular to a universal clamp for drilling holes in a vacuum clamping area of ​​an aircraft composite floor. Background Art

[0002] When processing the holes and the contours around the holes of aircraft composite floor parts, a clamping mechanism consisting of a pressure plate, bolts and nuts is mainly used. Such parts are relatively large and require more clamping mechanisms. During processing, multiple identical clamping mechanisms need to be arranged around the aircraft composite floor. Workers need to clamp them one by one, and the clamping mechanisms need to be disassembled to avoid the tool. The clamping mechanisms are then reinstalled after the processing is completed. During the entire process of loading and unloading workpieces, workers frequently install and disassemble the clamping mechanisms, which results in considerable labor intensity and low production efficiency. At the same time, it is not appropriate to use traditional vacuum adsorption clamping because aircraft composite floor parts are prone to air leakage after multiple through-holes are processed, which leads to vacuum failure and vacuum adsorption clamping failure. Summary of the invention

[0003] The technical problem solved by the present invention is to provide a universal fixture for drilling holes in a vacuum clamping area of ​​an aircraft composite floor, so as to solve the problems in the above-mentioned background technology.

[0004] The technical problem solved by the present invention is achieved by adopting the following technical solutions:

[0005] A universal fixture for drilling holes in a vacuum clamping area of ​​an aircraft composite floor, comprising a vacuum adsorption platform, a welding base, an exhaust system for connecting a vacuum pump, a workpiece, a leakage delay mechanism and a sealing ring, wherein the vacuum adsorption platform is screwed onto the welding base, an exhaust groove and an exhaust hole for connecting the exhaust system are arranged on the upper portion of the vacuum adsorption platform, the exhaust system is placed in the welding base, the sealing ring is pressed into the exhaust groove, the leakage delay mechanism is laid on the sealing ring, and the workpiece is placed on the leakage delay mechanism.

[0006] In the present invention, a reference hole is provided on the upper portion of the vacuum adsorption platform for correcting the position of the workpiece.

[0007] In the present invention, a plurality of air extraction grooves are symmetrically arranged on the upper portion of the vacuum adsorption platform.

[0008] In the present invention, no less than 4 air extraction holes are arranged on the upper part of the vacuum adsorption platform.

[0009] In the present invention, the exhaust system includes a diverter plate, a double outer thread ball valve, a hexagonal plug, a quick connector, an outer cone nozzle, a rubber gasket, a tube bundle plate, a PVC steel wire transparent hose, a three-way pipe joint and a reducer, wherein the diverter plate is installed on the tube bundle plate, four pairs of double outer thread ball valves are symmetrically installed on the diverter plate, one end of the PVC steel wire transparent hose is connected to the double outer thread ball valve, the other end of the PVC steel wire transparent hose is connected to the outer cone nozzle, the outer cone nozzle is installed at the lower end of the exhaust hole and is sealed by a rubber gasket; a hexagonal plug is installed at one end of the diverter plate, and a quick connector is installed at the other end of the diverter plate, the quick connector is connected to the three-way pipe joint through the PVC steel wire transparent hose, the three-way pipe joint is connected to the reducer, and the reducer is connected to the vacuum pump.

[0010] In the present invention, a filter screen is installed at the upper end of the air extraction hole to prevent chips and protect the vacuum pump.

[0011] In the present invention, the air extraction amount of the air extraction hole is not less than the air leakage amount after drilling.

[0012] In the present invention, the leakage delaying mechanism is a wood fiberboard or a combination of a wood fiberboard and a sealing film. When the workpiece has a regular structure, the wood fiberboard is used as the leakage delaying mechanism; when the workpiece has an irregular structure, the wood fiberboard is used as the leakage delaying mechanism, and a sealing film is laid on the wood fiberboard that is not covered on the workpiece to enhance the sealing and versatility.

[0013] In the present invention, when drilling holes in the vacuum clamping area of ​​aircraft composite floor, firstly, a suitable wood fiberboard is selected according to the length and width specifications of the workpiece, and then a sealing area is determined by indenting a certain distance around the wood fiberboard. After the sealing ring is pressed into the air extraction groove, the wood fiberboard is laid, and the workpieces are placed on the wood fiberboard in sequence. Finally, the double outer thread ball valve located in the sealing area for controlling the air extraction of the air extraction hole is opened according to the length and width specifications of the workpiece, and the vacuum pump is turned on at the same time. At this time, the workpiece is in a vacuum clamping state, and the drilling and peripheral contour processing of the workpiece are started. After drilling, air leakage occurs, but the air extraction speed is greater than the air leakage speed, and the vacuum clamping force is still stable. After the processing is completed, the vacuum pump is turned off and the workpiece is taken away.

[0014] Beneficial effects:

[0015] 1) The present invention can break through the process requirement that large-diameter through holes cannot be drilled in the vacuum clamping area, greatly reduce the labor intensity of workers, and improve production efficiency;

[0016] 2) The present invention can achieve the required vacuum degree in the non-sealed state and ensure the stability of the vacuum clamping force during the cutting process;

[0017] 3) The present invention is applicable to drilling holes and milling peripheral contour processing of aircraft composite floor parts of different specifications and sizes, has strong versatility, reduces the number of tooling, and effectively reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of workpiece processing in a preferred embodiment of the present invention.

[0019] Figure 2 It is a schematic diagram of the structure of the air adsorption platform and the air extraction system in the preferred embodiment of the present invention.

[0020] Figure 3 Schematic diagram of the structure of the air extraction system in a preferred embodiment of the present invention.

[0021] Figure 4 Schematic diagram of the processing principle of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below with reference to specific diagrams.

[0023] See also Figures 1 to 4 A universal fixture for drilling holes in a vacuum clamping area of ​​an aircraft composite floor, comprising a vacuum adsorption platform 1, a reference hole 2, a lifting bolt 3, a welding base 4, a vacuum system 5, a vacuum groove 6, a vacuum hole 7, a workpiece 8, a wood fiberboard 9 and a sealing ring 10, wherein the vacuum adsorption platform 1 is screwed on the welding base 4, the upper part of the vacuum adsorption platform 1 is provided with a reference hole 2 for calibrating the workpiece 8, a vacuum groove 6 and a vacuum hole 7 for connecting the vacuum system 5, the vacuum system 5 is placed in the welding base 4, the sealing ring 10 is pressed into the vacuum groove 6, the wood fiberboard 9 is laid on the sealing ring 10, and the workpiece 8 is placed on the wood fiberboard 9; and a lifting bolt 3 is provided on the welding base 4 for lifting the welding base 4.

[0024] In this embodiment, the exhaust system 6 includes a diverter plate 61, a one-inch double outer thread ball valve 62, a one-inch hexagonal plug 63, a one-inch quick connector 64, an outer cone nozzle 65, a rubber gasket 66, a bundle tube plate 67, a PVC steel wire transparent hose 68, a three-way pipe joint 69, a screw 610, a reducer 611 and an exhaust outlet 612. The diverter plate 61 is installed on the bundle tube plate 67 by screws 610. Four pairs of one-inch double outer thread ball valves 62 are symmetrically installed on the diverter plate 61. The one-inch double outer thread ball valve 62 is connected to the steel wire through the steel wire. The PVC steel wire transparent hose 68 is connected to the outer cone nozzle 65, which is installed at the lower end of the exhaust hole 7 and sealed by a rubber gasket 66; a one-inch hexagonal plug 63 is installed at one end of the diverter plate 61, and a one-inch quick connector 64 is installed at the other end of the diverter plate 61. The one-inch quick connector 64 is connected to the three-way pipe joint 69 through the PVC steel wire transparent hose 68, and the three-way pipe joint 69 is connected to the reducer 611, and the reducer 611 is connected to the vacuum pump. The three-way pipe joint 69 is provided with an exhaust outlet 612.

[0025] In this embodiment, a filter screen is installed at the upper end of the air extraction hole 7 to prevent chips and protect the vacuum pump.

[0026] In this embodiment, if Figure 1 As shown, the workpiece 8 is mostly more than 2 meters in length, light in weight, thin in thickness, large in area, and with a processing hole diameter of more than 10 mm. The parts of the workpiece 8 that need to be processed are the workpiece peripheral contour 81 and the workpiece through hole 82. The vacuum adsorption clamping has high processing efficiency. However, after the workpiece 8 is processed with multiple workpiece through holes 82 with a diameter of more than 10 mm, the vacuum is easily destroyed. The way to solve the restricted factor is: in the case of vacuum destruction, continue to maintain the vacuum degree. For this purpose, according to the vacuum clamping force principle, combined with the large area, light weight and small cutting force of aircraft composite floor parts during processing, a lower vacuum degree is selected; after the vacuum adsorption area drilling processing is completed, the vacuum adsorption sealing state is destroyed, the residual air pressure (P0) will gradually increase, and the vacuum degree will decrease. To ensure sufficient vacuum degree, the present embodiment uses the exhaust system 6 to control the residual air pressure (P0), and the vacuum clamping force is calculated according to the vacuum degree of the vacuum adsorption platform 1 cavity. To obtain sufficient clamping force, the vacuum degree is required to be maintained within a certain range. When the vacuum adsorption platform 1 cavity is absolutely vacuum, the suction force acting on the workpiece 8 is 1 kg / cm 2 (P a ), that is, one atmosphere, in fact, due to the residual pressure (P 0 ) exists, it is difficult to achieve absolute vacuum in the cavity of the vacuum adsorption platform 1, and the real pressure P = Pa-P 0 That is, when the effective area of ​​the workpiece 8 (i.e., the projected area of ​​the surface of the vacuum adsorption platform 1 bounded by the sealing ring 10) is large and the cutting force is small, a lower vacuum degree can be selected. Otherwise, a higher vacuum degree should be selected. According to this principle, the following measures are adopted:

[0027] 1) Increase the number of exhaust holes 7

[0028] Expand the width of the air extraction groove 6, enlarge the diameter of the air extraction hole 7, and increase the number of the air extraction holes 7;

[0029] 2) Adding a structure to delay leakage

[0030] A wood fiberboard 9 is laid between the workpiece 8 and the vacuum adsorption platform 1. After the through holes are processed, the wood fiberboard 9 is used to slow down the air leakage speed. The wood fiberboard 9 can not only prevent the airflow from entering quickly, but also meet the airflow passing through the vacuum adsorption area under the state of exhausting air, so as to firmly adsorb the workpiece 8. In addition, the wood fiberboard 9 can also protect the tool;

[0031] At the same time, the air extraction volume of the air extraction hole 7 is not less than the air leakage volume after drilling;

[0032] The above-mentioned method ensures that during the processing of the workpiece 8, when the vacuum is broken, the vacuum adsorption platform 1 can still maintain the required vacuum degree, thereby ensuring an effective vacuum clamping force.

[0033] In this embodiment, the vacuum adsorption platform 1 and the welding base 4 are screwed. This design is to prevent deformation on the one hand, and to facilitate the installation of the exhaust pipeline of the exhaust system 6 on the other hand. In order to improve the versatility, it is suitable for the processing of aircraft composite floor parts of different specifications and sizes. The sealing groove set in this embodiment is equal to the exhaust groove 6, and the groove width is unified. The sealing area is randomly arranged according to the size of the workpiece 8; it can be selected and used according to the size of the workpiece, and the switch is controlled by the one-inch double outer thread ball valve 2.

[0034] In this embodiment, the processing principle of the workpiece 8 is as follows:

[0035] Processing Figure 1 Taking the workpiece 8 shown as an example, a wood fiberboard 9 of corresponding size is selected according to the length and width specifications of the workpiece 8, and a sealing ring 10 is set below the position indented by a certain distance around the wood fiberboard 9. The operation sequence is as follows: according to the size of the workpiece 8, the length and width specifications of the wood fiberboard 9 are selected, and the sealing area is determined. After the sealing ring 10 is pressed into the exhaust groove 6, the wood fiberboard 9 is laid, and then the workpiece 8 is placed on the wood fiberboard 9, and the three groups of one-inch double outer thread ball valves 2 for controlling the exhaust holes 7 in the sealing area are opened, and the other five groups of one-inch double outer thread ball valves 2 of the exhaust pipelines are closed, and the vacuum pump is turned on. At this time, the workpiece 8 is in a vacuum clamping state, and the drilling and peripheral contour processing of the workpiece 8 are started. After drilling, air leakage occurs, but the exhaust speed is greater than the air leakage speed, and the vacuum clamping force is still stable; after the processing is completed, the vacuum pump is turned off, and the workpiece 8 is taken away. The vacuum clamping effectively saves the assembly and disassembly time of the clamping mechanism composed of the pressing plate, bolts and nuts, and improves production efficiency;

[0036] When the workpiece 8 is an irregular shape such as a trapezoid, and the wood fiberboard 9 is a rectangle or a square, and the sealing area is indented around the wood fiberboard 9, a sealing film is laid on the wood fiberboard 9 not covered by the workpiece 8 to enhance the sealing and versatility.

[0037] The protection scope of the present invention is not limited to the technical solutions disclosed in the specific implementation methods. All modifications, equivalent substitutions, improvements, etc. made according to the technical implementation of the present invention are within the protection scope of the present invention.

Claims

1. A universal fixture for drilling holes in vacuum clamping areas of aircraft composite floors, comprising a vacuum adsorption platform, a welding base, an exhaust system for connecting a vacuum pump, a workpiece, a leakage delay mechanism and a sealing ring, characterized in that: The vacuum adsorption platform is screwed on the welding base. An exhaust groove and exhaust holes for connecting the exhaust system are arranged on the upper part of the vacuum adsorption platform. The exhaust system is placed in the welding base. The sealing ring is pressed into the exhaust groove. The leakage delay mechanism is laid on the sealing ring, and the workpiece is placed on the leakage delay mechanism.

2. A universal fixture for drilling holes in vacuum clamping areas of aircraft composite floors according to claim 1, characterized in that: A reference hole is arranged on the upper part of the vacuum adsorption platform.

3. The universal fixture for drilling holes in vacuum clamping areas of aircraft composite floors according to claim 1, characterized in that: A plurality of air extraction grooves are symmetrically arranged on the upper part of the vacuum adsorption platform.

4. The universal fixture for drilling holes in vacuum clamping areas of aircraft composite floors according to claim 1, characterized in that: No less than 4 air extraction holes are arranged on the upper part of the vacuum adsorption platform.

5. The universal fixture for drilling holes in vacuum clamping areas of aircraft composite floors according to claim 1, characterized in that: The exhaust system includes a diverter plate, a double outer thread ball valve, a hexagonal plug, a quick connector, an outer cone nozzle, a rubber gasket, a tube bundle plate, a PVC steel wire transparent hose, a three-way pipe joint and a reducer, wherein a diverter plate is installed on the tube bundle plate, four pairs of double outer thread ball valves are symmetrically installed on the diverter plate, one end of the PVC steel wire transparent hose is connected to the double outer thread ball valve, the other end of the PVC steel wire transparent hose is connected to the outer cone nozzle, the outer cone nozzle is installed at the lower end of the exhaust hole and is sealed by a rubber gasket; a hexagonal plug is installed at one end of the diverter plate, and a quick connector is installed at the other end of the diverter plate, the quick connector is connected to the three-way pipe joint through the PVC steel wire transparent hose, the three-way pipe joint is connected to the reducer, and the reducer is connected to the vacuum pump.

6. The universal fixture for drilling holes in vacuum clamping areas of aircraft composite floors according to claim 1, characterized in that: A filter is installed on the upper end of the air extraction hole.

7. The universal fixture for drilling holes in vacuum clamping areas of aircraft composite floors according to claim 1, characterized in that: The air extraction volume of the exhaust hole shall not be less than the air leakage volume after drilling.

8. The universal fixture for drilling holes in vacuum clamping areas of aircraft composite floors according to claim 1, characterized in that: The air leakage delaying mechanism is a wood fiber board or a combination of a wood fiber board and a sealing film.

9. A universal fixture for drilling holes in a vacuum clamping area of ​​an aircraft composite floor according to any one of claims 1 to 8, characterized in that: When drilling holes in the vacuum clamping area of ​​aircraft composite floors, first select a suitable wood fiberboard according to the length and width specifications of the workpiece, then indent a certain distance around the wood fiberboard to determine the sealing area, and then press the sealing ring into the exhaust groove, lay the wood fiberboard, and place the workpieces on the wood fiberboard in turn. Finally, open the double outer thread ball valve located in the sealing area for controlling the exhaust hole according to the length and width specifications of the workpiece, and turn on the vacuum pump at the same time. At this time, the workpiece is in a vacuum clamping state, and the drilling and peripheral contour processing of the workpiece are started. After drilling, air leakage occurs, but the exhaust speed is greater than the leakage speed, and the vacuum clamping force is still stable; after processing, turn off the vacuum pump and remove the workpiece.

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