Undercarriage deep hole cavity machining method

Abstract

The invention provides an undercarriage deep hole cavity machining method. The undercarriage deep hole cavity machining method comprises the steps that firstly, a technological process is formulated, and a tower footing deep hole drilling machine, a cutter bar and a cutter head are selected according to the technological process; secondly, the tool bit and the tool bar are installed on a tower footing deep hole drilling machine, a deep hole primary hole is machined firstly, and a bottom hole is formed; thirdly, the bottom hole serves as a reference, and a tool is controlled to be expanded through a numerical control program to conduct profiling machining on the deep hole cavity; and machining is completed. According to the method, the machining technological process is reasonably designed, the tool bar and the tool bit for machining are reasonably selected, the machining allowance is determined according to the technological process and the type and the size of the tool bit, the deep hole complex cavity near-size variable-diameter machining numerical control program is compiled, deep hole cavity near-size variable-diameter machining is completed, and the product machining efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal parts cutting and processing, and in particular to a method for processing a landing gear deep hole cavity. Background Art

[0002] The main bearing outer tube of the current aircraft landing gear has complex inner cavity with high precision, large overhang and high processing quality requirements, such as Figure 3 As shown, its aspect ratio is 14:1, the inner hole profile of the outer cylinder is complex, and the R angle, taper angle and taper of the cavity at the bottom of the hole coexist.

[0003] At present, the pre-heating process for processing such structures adopts rough machining and semi-finishing methods, as shown in Figure 1, in which reference numeral 101 is the blank hole interface; 102 is the final interface of the deep hole cavity; 103 is the deep hole cavity machining allowance; 104 is the reverse cavity; 105 is the large cone surface and the small cone surface in the reverse cavity; 106 is the arc surface in the reverse cavity; 107 is the reverse cavity entrance; 108 is the outer cavity; 109 is the large tool head for push boring; 110 is the medium tool head for push boring; 111 is the small tool head for push boring; 112 is the tool head for pull boring; 113 is the stepped shock-absorbing tool bar; 114 is the outer cavity processing; 115 is the reverse cavity rough processing and the middle processing of the large cone surface; 116 is the reverse cavity large cone surface processing tool head can reach the deepest position of the deep hole (axial direction); 117 is the reverse cavity large cone surface processing tool head can reach the shallowest position of the deep hole (axial direction); 118 is the distance L1 between the tool rod and the reverse cavity entrance hole wall; 119 is the distance L2 between the tool rod and the outer cavity hole wall; 120 is the reverse cavity large cone surface front processing and arc processing; 121 is the reverse cavity bottom straight hole processing; 122 is the reverse cavity small cone surface processing; 223 is the reverse cavity large cone surface rear processing.

[0004] The process is to first use deep hole drilling-boring-roughing to remove the excess, and then use different boring cutters to semi-finish to remove the excess. The processing process requires the replacement of equipment and tools, and the processing efficiency is low.

[0005] Therefore, it is of great significance to propose a method to improve product processing efficiency while using the same equipment and reducing tool changes. Summary of the invention

[0006] The purpose of the present invention is to provide a safe and reliable landing gear deep hole cavity processing method, which can effectively improve the deep hole processing efficiency, reduce the processing cost, and is suitable for processing complex surfaces of different geometric shapes in the deep hole.

[0007] The technical solution of the present invention is: a method for processing a landing gear deep hole cavity, comprising the following steps: Step 1: Develop a process flow and select the tower base deep hole drilling machine, tool bar and tool head according to the process flow; Step 2: Install the cutter head and the cutter bar on the tower base deep hole drilling machine, first process the deep hole initial hole, and form the bottom hole; Step three, using the bottom hole as a reference (such as a guide and support), the tool is controlled by a numerical control program to expand and profile the deep hole cavity to complete the processing.

[0008] Preferably, the tool head includes a deep hole drilling tool head, a bottom hole countersinking tool head and a deep hole complex cavity processing tool head, wherein the deep hole drilling tool head processes the deep hole initial hole, the bottom hole countersinking tool head processes the bottom hole, and the deep hole complex cavity processing tool head processes the deep hole cavity.

[0009] Preferably, the tool bar is selected based on the following ratio: hole depth of landing gear deep hole + oil receiver length + top plate length + shock absorber length + chip conveyor length < tool bar length L < tower base deep hole drilling machine guide rail - spindle box length.

[0010] Preferably, the deep hole complex cavity machining tool head selects an expandable tool, which refers to the bottom hole size and the expansion amount of the tool holder.

[0011] Preferably, in step one, it is also necessary to confirm whether a transfer sleeve is required between the tool rod and the tool, and to confirm the transmission ratio of the tool expansion in step three.

[0012] Preferably, in step three, the tool first reaches the bottom hole at the bottom of the cavity, and then feeds toward the hole mouth with the bottom hole as the starting point, and simultaneously drives the tool head to expand / contract to perform contour processing along the boundary of the deep hole cavity hole.

[0013] Preferably, the CNC program in step three is compiled according to the deep hole cavity profile.

[0014] Preferably, the variable values ​​of the numerical control program are driven by the Z-axis and X-axis dimensions, the starting tool point of the numerical control program is smaller than the bottom hole diameter, and the boring starting point is on the bottom hole.

[0015] Preferably, during the expansion process of the tool, its feed speed is F1, and when the tool processes the straight surface in the deep hole cavity, its feed speed is F2, and F1<F2.

[0016] Compared with the related art, the present invention has the following beneficial effects: 1. The landing gear deep hole cavity processing method is to reasonably design the processing process, reasonably select the tool bar and tool head for processing, determine the processing allowance according to the process and the type and size of the tool head, compile the deep hole complex cavity near-size variable diameter processing CNC program to complete the deep hole cavity near-size variable diameter processing, and improve the product processing efficiency; Second, the landing gear deep hole cavity processing method uses a tower base deep hole drilling machine and an unfolded tool (boring tool) to achieve large excess removal of more than 20 mm on a single side, improve deep hole processing efficiency by more than 80%, reduce processing costs, and can be widely used in the processing of complex surfaces of different geometric shapes in deep holes; 3. The present invention reasonably selects processing equipment, configures an unfolded boring tool and a tool bar, and compiles a deep hole variable diameter processing CNC program, which can achieve efficient processing with a single-side cutting depth of 20mm and an axial feed of 12mm / min. Compared with the traditional processing method of using a damping and shock-absorbing tool bar for segmented cutting on a CNC lathe, a single-side cutting depth of 1-2mm, and an axial feed of 8mm / min, the processing efficiency is improved by more than 10 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG1 is a conventional landing gear cavity processing method (wherein, Figure 1a This is the processing diagram 1. Figure 1b Tools used for processing, Figure 1c This is the processing diagram 2. Figure 1d For processing instructions Figure 3 , Figure 1e This is processing diagram 4. Figure 1f This is processing diagram 5. Figure 1g Processing schematic diagram 6); FIG2 is a method for processing a landing gear deep hole cavity provided by the present invention (wherein, Figure 2a This is a schematic diagram of solid drilling processing; Figure 2b This is a schematic diagram of countersink processing. Figure 2c is a schematic diagram of unfolded tool processing); Figure 3 This is a schematic diagram of the structure of a deep hole cavity of a certain type of landing gear. DETAILED DESCRIPTION

[0018] The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. For the convenience of description, if the words "upper", "lower", "left" and "right" appear in the following, they only indicate that the upper, lower, left and right directions are consistent with the drawings themselves, and do not limit the structure.

[0019] As shown in FIG2 , the reference numerals in the figure are: 201 is the bottom hole of the blank; 202 is a solid drill bit; 203 is the R angle of the bottom hole of the cavity; 204 is a bottom hole countersink drill bit; 205 is the boundary of the deep hole cavity hole; 206 is an expandable variable diameter cutter head; and 207 is a pull rod.

[0020] The present embodiment provides a method for processing a landing gear deep hole cavity, comprising the following steps: Step S1, formulate process flow The process flow includes the selection of a drilling machine and processing steps. The drilling machine may be a tower base deep hole drilling machine that supports X-axis drive.

[0021] Step S2, according to the process flow of step S1, select the deep hole processing tool bar The selection of the tool bar refers to the hole depth of the landing gear deep hole + oil collector length + top plate length + shock absorber length + chip conveyor length < tool bar length L < tower base deep hole drilling machine guide rail - spindle box length. After comprehensive consideration, a φ130mm×4500mm tool bar is selected.

[0022] Step S3, blade selection Step S3.1, deep hole drilling tool selection The deep hole drilling tool head is used to process the deep hole initial hole and form the bottom hole. In principle, the bottom hole is equal to or slightly smaller than the cavity diameter, and the cutting amount of the NC boring head (expandable variable diameter tool head 206) is reduced as much as possible. Since the bottom hole diameter of the cavity in the embodiment is φ139.9 mm, a φ139.9 mm solid drill 202 is selected.

[0023] Step S3.2, bottom hole countersink cutter selection The R angle 203 of the bottom hole of the cavity is 25mm, so a φ139.9R25 forming countersink is selected to process the R25 fillet.

[0024] Step S3.3, tool head selection for deep hole complex cavity machining When selecting an expanded tool, the size of the bottom hole and the expansion of the tool holder should be considered comprehensively. The maximum outer diameter nominal size of the expanded tool should be the same as the bottom hole, and the outer diameter tolerance of the expanded tool is recommended to adjust the guide bar to (-0.02, -0.05mm); the expansion of the tool holder should be able to cover the entire processing range.

[0025] In addition, after confirming the unfolded tool, confirm whether a transfer sleeve is required between the tool rod and the tool, whether the X-axis connecting rod needs to be adjusted, and confirm the tool expansion transmission ratio.

[0026] The processing principle of the unfolded tool: the unfolded tool can be regarded as an NC boring tool with a programmable tool head. Compared with the traditional boring tool which is subject to the disadvantages of hole depth, hole diameter, aspect ratio, tool vibration, tool letting, small cutting depth, etc., it has the advantages of one-cut forming, no hole depth limitation, large cutting depth, etc. When the unfolded tool is processed, it is first fed quickly to the bottom of the cavity, and then fed from the starting point of the bottom of the cavity toward the hole mouth. At the same time, the pull rod 207 drives the unfolded variable diameter tool head 206 to expand / contract to perform contour processing along the boundary 205 of the deep hole cavity (such as Figure 2c as shown).

[0027] Step S4, using the bottom hole as a guide and support, and controlling the tool to expand and profile the deep hole cavity through a numerical control program to complete the processing.

[0028] When compiling a program, compile the CNC program according to the cavity contour, and the programming principle is consistent with that of the CNC lathe. The variable values ​​of the CNC program are mainly driven by the Z-axis and X-axis dimensions; the starting point of the program should be smaller than the bottom hole diameter, and the starting point of boring and drawing should be selected at the bottom of the hole; the F value (feed speed) during the X-axis expansion process should not be too large. When boring and drawing a straight surface, the F value can be appropriately increased, and the inclined surface can reduce the feed F value; correctly select the G02\G03 command according to the R angle. The details are as follows: ①Deep hole CNC program N10 G01 G94 Z-1995 F20 N20 G01 Z-1994 N30 M1=5 M2=5 N40 M63 ② Bottom hole countersinking NC program N10 G01 G94 Z-1990 F800 (rapid feed close to the bottom of the hole) N20M1=3 S1=150 M2=3 S2=25 N30 G01Z-2026 F10 (speed reduction for R angle processing) N40 G01 Z-2035.3 F5 N50 G01 -2036.815 F3 N60 G01 Z-2035.3 F1 N70 G01 Z-2025 F20 N80 M1=5 M2=5 N90 M63 ③ Deep hole complex cavity machining CNC program N10 G01 G94 Z-1947 F500; (enter the starting point of boring at the bottom of the hole) N20 M62 N30 M76 N40 G04 F5 N50 G01 X138.9 Z-1943.448 F5; (X value is less than the bottom hole φ139.9, the inclined surface extends from the space point to prevent scratches and chipping, and the F value should not be too large during the X-axis expansion process to ensure the surface quality of the inclined surface) N60 G01 X141.534 Z-1938.533 N70 G01 X169.594 Z-1903.807 N80 G02 X170.264 Z -1902.085 CR=4.596; (Note that the G02\G03 command should be selected correctly according to the R angle) N90 G01 Z-1416.996 F10; (When processing straight surface boring, F can be appropriately increased) N100 G01 X183.854 Z-1232.162 F5; (inclined surface lowers feed F) N110 G02 X165.392 Z-1205.275 CR=39.568 N120 G01 X159 Z-1201.166 N130 G01 Z-1148.622 F10 N140 G01 X138.9 Z-1126.05 According to the above CNC program, the near-size variable diameter processing of the deep hole cavity is completed.

[0029] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for processing a landing gear deep hole cavity, characterized in that: The steps include: Step 1: Develop a process flow and select the tower base deep hole drilling machine, tool bar and tool head according to the process flow; Step 2: Install the cutter head and the cutter bar on the tower base deep hole drilling machine, first process the deep hole initial hole, and form the bottom hole; Step three, using the bottom hole as a reference, and controlling the tool to expand and profile the deep hole cavity through a numerical control program to complete the processing.

2. The landing gear deep hole cavity processing method according to claim 1, characterized in that: The tool heads include a deep hole drilling tool head, a bottom hole countersinking tool head and a deep hole complex cavity processing tool head, wherein the deep hole drilling tool head processes the deep hole initial hole, the bottom hole countersinking tool head processes the bottom hole, and the deep hole complex cavity processing tool head processes the deep hole cavity.

3. The landing gear deep hole cavity processing method according to claim 2, characterized in that: The selection of the tool bar refers to the hole depth of the deep hole of the landing gear + the length of the oil collector + the length of the top plate + the length of the shock absorber + the length of the chip conveyor < the tool bar length L < the guide rail of the tower base deep hole drilling machine - the length of the spindle box.

4. The landing gear deep hole cavity processing method according to claim 2, characterized in that: The deep hole complex cavity processing tool head selects an expandable tool, which refers to the bottom hole size and the expansion amount of the tool seat.

5. The landing gear deep hole cavity processing method according to claim 1, characterized in that: In step one, it is also necessary to confirm whether a transfer sleeve is required between the tool rod and the tool, and to confirm the transmission ratio of the tool expansion in step three.

6. The landing gear deep hole cavity processing method according to claim 1, characterized in that: In step three, the tool first reaches the bottom hole at the bottom of the cavity, and then feeds toward the hole mouth with the bottom hole as the starting point, and at the same time drives the tool head to expand / contract to perform contour processing along the boundary of the deep hole cavity.

7. The landing gear deep hole cavity processing method according to claim 1, characterized in that: The numerical control program in step three is compiled according to the deep hole cavity profile.

8. The landing gear deep hole cavity machining method according to claim 1, characterized in that: The variable value of the numerical control program is driven by the Z-axis and X-axis dimensions. The starting tool point of the numerical control program is smaller than the bottom hole diameter, and the boring starting point is on the bottom hole.

9. The landing gear deep hole cavity processing method according to claim 1, characterized in that: During the expansion process of the tool, its feed speed is F1. When the tool processes the straight surface in the deep hole cavity, its feed speed is F2, F1<F2.

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