Group cutter for assembling, finish machining and reaming of multiple groups of connecting holes at unequal intervals of airplane

Abstract

The invention relates to a grouped cutter for assembling, finish machining and reaming multiple groups of connecting holes at unequal intervals of an airplane, and belongs to the technical field of airplane assembling. Through the combined structural design of the cutter cutting part, the lengthening rods and the switching device, only the lengthening rods with different lengths in the middle are replaced according to different depths of machined holes, so that cutter conversion and combination as well as geometric angle optimization of materials, front angles, rear angles, helical angles, cutting taper angles and the like of the cutters can be quickly completed; by means of the front guide structure, the rear guide structure and the double-universal power transmission device, it is guaranteed that coaxiality of a plurality of sets of super-long holes is achieved, precise machining of involution of parts made of materials difficult to cut can be achieved, cutting machining can be completed, and the size precision and the surface roughness meet the technical requirements; the method can be applied to assembly machining of similar structural components in the aircraft assembly aviation field and has important application and popularization value.

Description

Technical Field

[0001] The present invention relates to a set of tools for finish machining reaming of unequal-spacing multi-group connecting holes in aircraft assembly, belonging to the technical field of aircraft assembly. Background Art

[0002] During the aircraft assembly process, when two parts with unequal-spacing multi-group connecting holes are assembled and processed, finish machining of the combined connecting piece holes is required. The two connecting pieces are long, with high precision and high coaxiality requirements, and the material is difficult-to-machine material. This is the most critical finish machining in aircraft assembly. The materials of the combined parts are titanium alloy and stainless steel respectively. The hole structure of the combined part consists of multiple groups of unequal-spacing and discontinuous holes. First, finish machining of the holes is carried out, and then connection is made. This state is the first machining. The two materials of the parts here are both difficult-to-machine materials. After combination, the machining distance is long, chip removal of the tool is difficult, the total length of the machined holes is extremely long, the length-diameter ratio is large, the dimensional accuracy and coaxiality requirements of the holes are high, and only automatic feed drilling can be used for power during machining, which is very difficult. Summary of the Invention

[0003] The present invention belongs to the field of manufacturing process equipment for aircraft assembly processing. The present invention relates to a method for formulating a machining method and developing a tool for finish machining of two long and difficult-to-machine material parts with unequal-spacing multi-group connecting holes during the aircraft component assembly process, to ensure high-precision and high-coaxiality requirements.

[0004] The purpose of the present invention is to provide a machining method and a set of finish machining reaming tools for ultra-long multi-group unequal-spacing non-continuous connecting holes composed of two difficult-to-machine materials, titanium alloy and stainless steel, during the aircraft product assembly process.

[0005] According to one aspect of the present application, there is provided a set of tools for finish machining reaming of unequal-spacing multi-group connecting holes in aircraft assembly, which is composed of a reaming tool part Ⅰ, an extension rod Ⅱ, and a power transfer part Ⅲ;

[0006] The reaming tool part Ⅰ includes a front guide 1, a tool cutting part 2, a rear guide 3, and a quick-change shank 4;

[0007] The extension rod Ⅱ includes a working head 6, a connecting pin 5, and a quick-change structure 7;

[0008] The power transfer part Ⅲ includes a quick-change joint 8, a connecting pin 9, a cross block 10, a hexagonal mounting and tightening part 11, a threaded shank 12, a pin 13, a sleeve 14, and a retaining pin 15.

[0009] The cutting part 2 of the tool adopts a cutting cone angle of 2°±1°. The lengthened cutting cone length reduces the cutting amount per revolution, reduces the cutting resistance, and enables smooth cutting. A rake angle of 0° is adopted, which is beneficial for chip breaking and chip evacuation, improves the heat dissipation condition of the tool, and enhances the strength of the cutting edge. The first back angle of both the cutting cone and the calibration part is 13°±1°, and the second back angle is 20°. The starting point of the second back angle is at the 1 / 2 of the blade thickness. The tool body back angle is 30°, which overcomes the friction caused by springback. The tool appropriately increases the back angle, reduces the cutting temperature caused by friction, avoids chip sticking, reduces the cutting resistance caused by friction, and at the same time ensures that the cutting teeth have sufficient cutting strength. A helix angle of 5°±1° right-handed helix is adopted for smooth cutting and high cutting efficiency.

[0010] The quick-change shank 4 adopts a quick-change structure, which is easier to disassemble and assemble in a narrow operating space.

[0011] The quick-change shank 4 is connected to the extension rod II. Rotating the extension rod II clockwise can tighten the reaming tool part I through the connecting pin 5.

[0012] The connecting pin 5 is fastened at the working head 6 by interference fit for power transmission.

[0013] The quick-change structure 7 is located at the tail of the extension rod II.

[0014] The head end of the extension rod II is connected to the reaming tool part I through the quick-change shank 4, and the tail end is connected to the quick-change joint 8 of the power transfer part III through the quick-change structure 7.

[0015] The pin 13 is a long pin with a hole in the middle, which has an interference fit with the quick-change joint 8 and a clearance fit with the cross block 10. The sleeve 14 is a two-section bushing structure, connecting the fork ear of the power transfer part III and the cross block 10. The retaining pin 15 is a long pin with a small diameter. The retaining pin 15 has a clearance fit with the middle hole of the pin 13 and the inner holes of the two sections of the sleeve 14. After installation, it opens 60 degrees and is flanged and fastened.

[0016] The connecting pin 9 is fastened at the mating part of the quick-change joint 8 by interference fit for power transmission.

[0017] The cross block 10, pin 13, sleeve 14, and retaining pin 15 form a double universal joint structure.

[0018] One end of the quick-change joint 8 is connected to the extension rod II, and the other end is mated with the cross block 10 of the double universal joint structure. The double universal joint structure is connected to the hexagonal installation and tightening part 11, and the tail of the hexagonal installation and tightening part 11 is a threaded shank 12.

[0019] The hexagonal mounting tightening part 11 installs the power transfer part III to the tightening part of the automatic feed drill. The width is larger than the standard wrench width and the size is in accordance with the standard wrench specification. The threaded handle adopts 9 / 16″ and cooperates with the automatic feed drill to complete the power transmission.

[0020] The tail of the power transfer part III is connected to the automatic feed drill through a threaded handle 12 to achieve quick connection and power transmission.

[0021] According to the length of the processed hole, the extension rod II can be divided into a series of extension rods of different lengths, and extension rods of different lengths are used in different processing stages.

[0022] The specific processing method is: fix the combined connector on the special tooling, install the tooling positioning hole at the position with relatively large spacing, and install a bushing with good wear resistance on the positioning hole. The feed power device adopts an automatic feed drill. The finishing tool adopts a combined tool structure, including a tool part that bears the cutting function, a power transfer part connected to the automatic feed drill, and an extended tool bar part of different lengths that can be quickly replaced. The cutting tool part is connected to the power part, and a combined tool of different lengths is formed to complete the processing of connecting holes at different positions until all connecting holes are finished. The spacing of the parts is unequal, the space is limited, and the processing distance is long. Special considerations must be made in the calculation and structural design of the tool cutting part in the length direction. Among them, the cutting tool part is composed of front and rear guides, cutting edges, and connecting parts. When calculating the length of the front and rear guides, it must be calculated according to the different spacing of the parts to ensure that one hole is in the front guide and one hole is in the rear guide, and at the same time ensure that the total length of the tool can be put in within the spacing. In order to avoid the rigid connection of the tool and ensure the coaxiality of the processing of multiple sets of connecting holes, the power part adopts a double universal structure.

[0023] The cutting part of the tool adopts an unequally divided six-tooth structure to reduce periodic chatter marks and improve the quality of the machined surface. The height of the tool body is 0.3mm smaller than the blade, which is convenient for grinding. The front guide 1 and rear guide 3 of the tool are matched with the bushing of the tooling with H7 and f7 clearances. Since the tool is long and has a complex shape, a structure with welded carbide blades is adopted to ensure the cutting of titanium alloy and stainless steel. The height of the tool body is 0.3mm smaller than the blade. The handle adopts a quick-change structure, which is easier to disassemble and assemble in a narrow operating space.

[0024] The extension rod II part can be divided into three or four extension rods of different lengths according to the length of the hole to be processed. The short rod is used at the beginning of processing and the long rod is used at the end. During the tool changing process, the two ends of the tool rod are connected to the tool part and the adapter through a quick-change structure, which makes disassembly and assembly particularly easy and fast.

[0025] By simply replacing the intermediate extension rod according to the different depths of the machined holes, the rapid completion of the tool transformation combination can be achieved.

[0026] The power transfer part Ⅲ adopts a double universal joint structure, which can ensure the coaxiality of the front and rear of the long hole and prevent the axis from skewing. That is, the double universal joint structure part is used to achieve a good matching effect between the front and rear guides and the tooling bushing, rather than one-way skew, and also reduces the influence of self-weight due to the too long tool, thereby ensuring the coaxiality accuracy requirements of hole machining.

[0027] The beneficial effects of the present invention are as follows: Through the combined structure design of the three parts of the tool cutting, the extension rod, and the transfer device, by simply replacing the intermediate extension rods with different length series according to the different depths of the machined holes, the rapid completion of the tool transformation combination can be achieved. The geometric angles such as the material, rake angle, clearance angle, helix angle, and cutting cone angle of the tool are optimized, and the front and rear guide structures and the double universal joint power transmission device ensure the coaxiality of the ultra-long multi-group holes. The group tool design can achieve the precise machining of the mating of difficult-to-cut material parts, can complete the cutting machining, and the dimensional accuracy and surface roughness meet the technical requirements. It can be applied to the assembly processing of similar structural parts in the aircraft assembly aviation field and has important popularization and application value. Brief Description of the Drawings

[0028] Figure 1 It is the general assembly drawing of the reaming group tool.

[0029] Figure 2 It is the structural schematic diagram of the tool; in the figure, ω is the helix angle of the reaming tool.

[0030] Figure 3 (a) is Figure 2 The partial sectional view of the cutting part of the tool in Figure 3 (b) is Figure 3 The sectional view along the C-C plane in (a); Figure 3 (c) is Figure 3 The sectional view along the D-D plane in (a); in the figure, Kr is the cutting cone angle of the reaming tool, γ is the rake angle of the reaming tool, α1 is the first clearance angle of the cutting cone and calibration part of the reaming tool, α2 is the second clearance angle of the cutting cone and calibration part of the reaming tool, and α3 is the clearance angle of the back of the tool body tooth of the reaming tool.

[0031] Figure 4 It is the structural schematic diagram of the extended tool rod.

[0032] Figure 5 (a) is the power transfer device diagram; Figure 5 (b) is Figure 5 (a) The sectional view along the A-A plane, in the figure, θ is the opening angle of the cotter pin 15.

[0033] Among them, Ⅰ is the reaming tool part, Ⅱ is a series of extension rods with different lengths, Ⅲ is the power transfer device, 1 is the front guide of the reaming tool, 2 is the cutting part of the reaming tool, 3 is the rear guide of the reaming tool, 4 is the quick-change shank of the reaming tool, 5 is the connecting pin, 6 is the working head of the tool rod, 7 is the quick-change tail of the tool rod, 8 is the quick-change joint, 9 is the connecting pin, 10 is the cross block, 11 is the hexagonal installation and tightening part, 12 is the threaded shank, 13 is the pin, 14 is the sleeve, and 15 is the retaining pin. Specific embodiments

[0034] The present application will be described in detail below in conjunction with embodiments, but the present application is not limited to these embodiments.

[0035] Embodiment 1

[0036] 1. Tool part:

[0037] (1) Since the tool is long and complex in shape, a structure form of welding hard alloy blades is adopted to ensure the cutting of titanium alloy and stainless steel. The blade material is Y330, and the tool body material is 9SiCr. The welding performance of the two materials is good.

[0038] (2) The front guide and rear guide of the tool and the bushing of the tooling adopt an H7 and f7 clearance fit, and the length is calculated according to the position of the tooling, the length of the part, and the length of the cutting edge.

[0039] (3) The number of tool teeth adopts an unequal six-tooth structure to reduce periodic vibration marks and improve the machining surface quality.

[0040] (4) Geometric angles of the tool: (a) A 0° rake angle is adopted, which is beneficial to chip breaking and chip evacuation, improves the heat dissipation conditions of the tool, and enhances the strength of the cutting edge. (b) The first relief angle of the cutting cone and the calibration part are both 13° ± 1°, the first relief angle is 25°, and the relief angle of the tool body is 30°. It overcomes the friction caused by springback. The tool appropriately increases the relief angle, reduces the cutting temperature caused by friction, avoids chip adhesion, reduces the cutting resistance caused by friction, and at the same time ensures that the cutting teeth have sufficient cutting strength. (c) A cutting cone angle of 2° ± 1° is adopted. The lengthened cutting cone length reduces the single revolution cutting amount, reduces the cutting resistance, and the cutting is stable. (d) A spiral angle of 5° ± 1° right helix is adopted for stable cutting and high cutting efficiency.

[0041] (5) The height of the tool body is 0.3 mm smaller than that of the blade.

[0042] (6) The shank adopts a quick-change structure, which is easier to disassemble and assemble in a narrow operating space. The fit between the shank and the tool rod adopts an H7 and g6 clearance fit.

[0043] 2. Extension rod part:

[0044] According to the different lengths of the holes to be machined, it can be divided into three or four extension rods with different lengths. The short rod is used at the beginning of machining, and the long rod is used for final machining. During the tool change process, both ends of the tool rod are of a quick-change structure with the tool and the adapter device respectively, and the disassembly and assembly are extremely easy and fast, and the H7 and g6 clearance fits are adopted. The connecting pins 5 and 9 are both φ3r6 and are interference-fitted with the extension tool rod and the quick-change joint φ3H7 respectively and fastened to the extension tool rod and the quick-change joint respectively.

[0045] 3. The power transfer part includes a quick-change joint, a connecting pin, a double universal joint composed of a cross block, a pin, a sleeve, and a snap pin, a hexagonal installation and tightening part, and a threaded shank.

[0046] The quick-change joint part is connected to the tail end of the extension tool rod. The double universal joint structure part can achieve a good matching effect between the front and rear guides and the tooling bushing, rather than one-way deflection, and also reduces the influence caused by the self-weight due to the too long tool length, thus ensuring the high-precision coaxiality requirement for hole machining.

[0047] The outer hexagonal part is to install the adapter device to the tightening part of the automatic feed drill. The width should be greater than the width of the standard wrench, and the size is according to the standard wrench specification. The threaded shank adopts 9 / 16″-18UNF-2A and is matched with the automatic feed drill to complete the power transmission.

[0048] When machining the assembly, first machine the farthest end and then the proximal end to prevent the chips from scratching the parts. When using the tool, first connect the power transfer part and the automatic feed drill firmly with a wrench relying on the 9 / 16″-18UNF thread; place the cutting part of the tool and the longest tool rod in the corresponding positions, first connect the two parts at the quick-change part, then connect the tail end of the tool rod with the power transfer, and then start machining.

[0049] The above are only the specific implementation manners of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can make several deformations or substitutions, which should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A group of tools for finish reaming of aircraft multi-group connection holes with unequal spacing, characterized in that it is composed of a reaming tool part Ⅰ, an extension rod Ⅱ, and a power transfer part Ⅲ; The reaming tool part Ⅰ includes a front guide (1), a tool cutting part (2), a rear guide (3), and a quick-change shank (4); The extension rod Ⅱ includes a working head (6), a connecting pin (5), and a quick-change structure (7); The power transfer part Ⅲ includes a quick-change joint (8), a connecting pin (9), a cross block (10), a hexagonal installation and tightening part (11), a threaded shank (12), a pin (13), a sleeve (14), and a retaining pin (15).

2. The group of tools for finish reaming of aircraft multi-group connection holes with unequal spacing according to claim 1, characterized in that The tool cutting part (2) adopts a cutting cone angle of 2° ± 1°. The length of the cutting cone is extended to reduce the cutting amount per revolution, reduce the cutting resistance, and make the cutting stable; it adopts a rake angle of 0°, which is beneficial to chip breaking and chip evacuation, improves the heat dissipation condition of the tool, and enhances the strength of the cutting edge; the first back angle of both the cutting cone and the calibration part adopts 13° ± 1°, the second back angle adopts 20°, the starting point of the second back angle is at 1 / 2 of the blade thickness, and the tool body back angle adopts 30°, which overcomes the friction caused by springback. The tool appropriately increases the back angle, reduces the cutting temperature caused by friction, avoids chip sticking, reduces the cutting resistance caused by friction, and at the same time ensures that the cutting teeth have sufficient cutting strength; it adopts a helix angle of 5° ± 1° right-handed helix for stable cutting and high cutting efficiency.

3. The group of tools for finish reaming of aircraft multi-group connection holes with unequal spacing according to claim 1, characterized in that The quick-change shank (4) adopts a quick-change structure, which is easier to disassemble and assemble in a narrow operating space.

4. The group of tools for finish reaming of aircraft multi-group connection holes with unequal spacing according to claim 1, characterized in that The quick-change shank (4) is connected to the extension rod Ⅱ. Rotate the extension rod Ⅱ clockwise, and the reaming tool part Ⅰ can be tightened through the connecting pin (5); The connecting pin (5) is fastened at the working head (6) by interference fit for power transmission; The quick-change structure (7) is located at the tail of the extension rod Ⅱ; The head end of the extension rod Ⅱ is connected to the reaming tool part Ⅰ through the quick-change shank (4), and the tail end is connected to the quick-change joint (8) of the power transfer part Ⅲ through the quick-change structure (7).

5. The group of tools for finish reaming of aircraft multi-group connection holes with unequal spacing according to claim 1, characterized in that The pin (13) is a long pin with a hole in the middle, which is in interference fit with the quick-change joint (8) and in clearance fit with the cross block (10). The sleeve (14) is a two-section bushing structure, connecting the fork ear of the power transfer part Ⅲ and the cross block (10). The retaining pin (15) is a small-diameter long pin, and the retaining pin (15) is in clearance fit with the middle hole of the pin (13) and the inner holes of the two sleeves (14). After installation, the opening is 60 degrees and is flanged and fastened.

6. The group of tools for finish reaming of aircraft multi-group connection holes with unequal spacing according to claim 1, characterized in that The connecting pin (9) is fastened at the mating part of the quick-change joint (8) by interference fit for power transmission; The cross block (10), pin (13), sleeve (14), and retaining pin (15) form a double universal joint structure; One end of the quick-change joint (8) is connected to the extension rod II, and the other end is mated with the cross block (10) of the double universal joint structure; the double universal joint structure is connected to the hexagonal mounting and tightening part (11), and the tail of the hexagonal mounting and tightening part (11) is a threaded shank (12).

7. The group of cutting tools for precision finishing reaming of aircraft non-uniform multi-group connecting holes according to claim 1, characterized in that The hexagonal mounting and tightening part (11) mounts the power transfer part III to the tightening part of the automatic feed drill. Its width is greater than the width of the standard wrench, and the dimensions are according to the standard wrench specifications.

8. The group of cutting tools for precision finishing reaming of aircraft non-uniform multi-group connecting holes according to claim 1, characterized in that The tail of the power transfer part III is connected to the automatic feed drill through the threaded shank (12) for quick connection and power transmission.

9. The group of cutting tools for precision finishing reaming of aircraft non-uniform multi-group connecting holes according to claim 1, characterized in that According to the different lengths of the holes to be machined, the extension rod II can be divided into a series of extension rods of different lengths, and extension rods of different lengths are used in different machining stages.

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