Processing method of small landing gear torsion arm

Abstract

This invention discloses a machining method for a small landing gear torsion arm. The method involves creating a connecting fixture based on the tooling interface position and form of the workpiece, pre-reserving a process interface on the workpiece blank, and connecting the workpiece to a vertical four-axis machining center to achieve workpiece positioning and clamping. The entire machining process achieves multi-stage machining in a single clamping operation. This invention's method features concentrated processes, simple operation, high machining efficiency, and easily guaranteed product quality, making it highly valuable for promotion and reference.

Description

Technical Field

[0001] This invention relates to machining processes, and in particular to a method for machining a small landing gear torsion arm. Background Technology

[0002] Typical workpiece structure of a small landing gear torsion arm is as follows: Figure 1 As shown, the overall structure is complex, with no flat surface for clamping and positioning, and the part contains features requiring high precision on all four sides. Using traditional machining methods, the part must first be pre-faced with pre-drilled process bosses. Then, a clamping plate is used to press the process bosses onto the worktable, and the part is flipped multiple times. A combination of vertical and horizontal machining centers is then used for machining. Finally, a fitter is required to manually finish and polish the part. Clearly, traditional machining methods require repeated clamping, which easily leads to clamping errors, making it difficult to guarantee the dimensional accuracy of the part, and creating multiple tool joints.

[0003] Furthermore, due to the small size of the part and the presence of numerous small corners, small-diameter tools are required for machining and corner clearing. Because of the presence of process bosses and pressure plates, the tool needs to be lengthened to avoid interference from the tool holder. Since the thickness of a standard pressure plate is generally greater than 20mm, lengthening the tool reduces its rigidity, making it prone to vibration during machining. This results in a rough surface finish on the part, and the excessively large length-to-diameter ratio of the tool necessitates a reduction in cutting speed, leading to low machining efficiency.

[0004] According to traditional processing methods, these types of parts need to be processed in a complementary manner using vertical and horizontal machining centers, resulting in dispersed product processes and increased time for parts transfer and auxiliary operations. Summary of the Invention

[0005] The technical problem to be solved by this invention is that, in the traditional processing method for small landing gear torsion arms, the processes are scattered, the tool overhang is long, the surface quality is poor, and the surface quality and dimensional accuracy are difficult to guarantee. This invention provides a processing method for small landing gear torsion arms that is centralized in process, simple to operate, has high processing efficiency, and makes it easy to guarantee product quality.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A method for manufacturing a small landing gear torsion arm, comprising the following steps:

[0008] Step S1: Based on the material, size, structural features, and the location and form of the tooling interface reserved in the process design of the workpiece being processed, fabricate the connecting tooling;

[0009] Step S2: Using a horizontal machining center, make a center hole at one end of the workpiece along the long end, and make a positioning reference surface, positioning hole and locking thread hole at the other end;

[0010] Step S3: Use connecting fixtures to connect the positioning reference surface, positioning hole and locking thread hole of the workpiece to completely restrict the degrees of freedom of the workpiece blank in all directions.

[0011] Step S4: Use the four-axis chuck of the vertical four-axis machining center to clamp the clamping part of the connecting fixture, and place the origin of the Y and Z axes of the vertical four-axis machining center on the center line of the clamping part of the connecting fixture, and place the origin of the X axis on the positioning reference surface of the workpiece. Insert the center of the vertical four-axis machining center into the center hole, and use a dial indicator to correct the runout of the workpiece to ensure that the runout of the workpiece is less than 0.03mm. Then, rough machine the top, bottom, left and right sides of the workpiece blank, leaving a 1mm allowance on each surface.

[0012] Step S5: Keep the workpiece blank in the same clamping state, loosen the center of the vertical four-axis machining center, and then tighten the center again.

[0013] Step S6: Recalibrate the X-axis origin of the workpiece and verify the runout of the workpiece relative to the clamping part;

[0014] Step S7: Finish machine all surfaces of the workpiece, except for the process chuck position, all surfaces and holes are machined to the final finished size of the workpiece;

[0015] Step S8: Remove the workpiece, dismantle the connecting fixture, use the shape of the workpiece for positioning, and use a vertical machining center to remove the process chuck.

[0016] Step S9: The tool is attached to the chuck position in the fitter's grinding process, and the surface of the workpiece is polished.

[0017] This invention designs non-standard tooling, reserves process interfaces on the workpiece blank, and connects the workpiece to a vertical four-axis machining center to achieve the positioning and clamping of the workpiece, enabling multi-process machining in a single clamping. As a result, the small landing gear torsion arm machining method of this invention has concentrated processes, is simple to operate, has high processing efficiency, and product quality is easy to guarantee, making it highly valuable for promotion and reference.

[0018] Preferably, a process boss is reserved at one end of the workpiece being processed, and the center of the process boss is provided with the center hole. The other end of the workpiece being processed is provided with the positioning reference surface, the positioning hole and the locking thread hole. The positioning hole includes a main positioning hole and a first connecting positioning hole, and the process boss is coaxial with the main positioning hole.

[0019] Preferably, the connecting fixture includes a positioning flange, one side of which is provided with a center positioning pin adapted to the main positioning hole and a second connecting positioning hole adapted to the first connecting positioning hole, and the other side is provided with a clamping part, and the positioning flange is provided with a plurality of connecting holes adapted to the locking thread hole.

[0020] Preferably, the length of the clamping portion is not less than 100mm.

[0021] Preferably, in step S6, if the X-axis origin of the workpiece to be processed exhibits a large fluctuation that fails to meet the processing accuracy requirements, then the connecting fixture and the workpiece to be processed need to be clamped together into the lathe, and the center hole needs to be recalibrated using the lathe tailstock.

[0022] Preferably, the thickness of the positioning flange is not less than 15mm. The clamping part adopts a φ10h7X12mm optical axis, and the second connecting positioning hole adopts a φ10H7 optical hole.

[0023] Preferably, in step S4, when using a vertical four-axis machining center, the length of the chuck clamping connection to the tooling clamping part is not less than 50mm. During machining, an ER32 tool holder or a tool holder with a diameter not exceeding that of the chuck is selected.

[0024] Preferably, in step S4, the safety height of the CNC program should be greater than the radius of the containment column of the workpiece and the tooling assembly by 30mm. The tool safety clamping length should ensure that the gap between the tool holder and the workpiece is greater than 2mm, and the gap between the tool holder and the highest point of the chuck jaws is greater than 10mm.

[0025] Preferably, in step S6, the recalibration of the origin needs to compensate for the offset in the X direction of the workpiece being processed, and verify the offset in the Y and Z directions.

[0026] Preferably, in steps S4 and S7, the origin of the X-axis of the workpiece should be placed on the positioning reference surface machined in step S2. The origins of the Y and Z axes should be placed at the center of the main positioning hole, and after assembly with the connecting fixture, the positioning reference surface of the connecting fixture is coaxial with the center of the main positioning hole.

[0027] Preferably, step S9 further includes deburring and polishing of the holes and surfaces processed to the final finished product size.

[0028] Compared with related technologies, the beneficial effects of the present invention are as follows:

[0029] 1. Based on the structure and blank shape characteristics of the part (workpiece), a special tooling is designed and a vertical four-axis machining center is used for machining. There is no need to use auxiliary tooling such as clamping plates. During machining, there is no need to consider the interference and avoidance between the tool and the clamping plate (used in traditional methods). This reduces the tool clamping length, enhances tool rigidity, increases cutting speed, greatly reduces vibration generated during cutting, and improves tool durability and part surface quality.

[0030] Second, using a vertical four-axis machining center allows for the machining of all features on all four sides of a part in a single setup, merging processes and reducing auxiliary time. Because there is no need to repeatedly clamp the part, clamping errors are eliminated, minimizing tool contact on the part surface and enhancing surface quality.

[0031] Third, this processing method is simple to operate, highly efficient and of high quality, and reduces the difficulty of programming and improves the efficiency of parts trial production.

[0032] The processing method of this invention enables efficient processing of small landing gear torsion arms, solving the problems of scattered processes, long clamping time, large tool length-to-diameter ratio, and low processing efficiency in such typical parts. It has strong promotion and reference value. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a typical structural diagram of a small landing gear torsion arm component, where a is the front view and b is the top view.

[0035] Figure 2 This is a schematic diagram of the connecting fixture provided by the present invention, where a is a front view and b is a right view.

[0036] Figure 3 This is a schematic diagram of the structure of the workpiece blank after preliminary processing according to the present invention, where a is a bottom view, b is a front view, and c is a top view.

[0037] Figure 4 This is a schematic diagram illustrating the clamping principle of the workpiece during the implementation of the process of this invention.

[0038] In the diagram: 1-Clamping part; 2-Center locating pin; 3-First connecting locating hole; 4-Connecting hole; 5-Center locating hole; 6-Second connecting locating hole; 7-Locking threaded hole; 8-Center hole; 9-Chuck clamping position of vertical four-axis machining center; 10-Center top position of vertical four-axis machining center; 11-Locking flange; 12-Locking datum surface; 13-Locking boss; 14-Workpiece to be machined; 15-Torque arm part; 151-First lug; 152-Second lug; 153-Connecting hole; 154-Center circular hole. Detailed Implementation

[0039] The present invention will be further described below with reference to specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0040] For ease of description, the relative positions of the components, such as top, bottom, left, right, etc., are described according to the layout direction of the accompanying drawings and do not limit the structure of this patent.

[0041] Figure 1 This is a structural diagram of a typical small landing gear torsion arm component. (Example) Figure 1 As shown, the torque arm component 15 has a triangular block structure. Its small end has a first lug 151, and each side of its large end has a second lug 152. Both the first lug 151 and the second lug 152 have connecting holes 153. A central circular hole 154 is also provided in the middle of the triangular block. The torque arm component blank is a free-forged product, and its size is 10mm larger than the component's containing block. The torque arm component needs to be machined from the blank as a whole, and high requirements are placed on its connecting holes 153, central circular hole 154, and all end faces.

[0042] The specific implementation method of machining torque arm parts using the small landing gear torque arm machining method of the present invention includes the following steps:

[0043] Step S1: Based on the material, size, and structural characteristics of the workpiece 14, and the location and form of the tooling interface reserved in the process design, fabricate the connecting tooling to the four-axis chuck: (e.g., ...) Figure 2 As shown, the connecting fixture includes a 15mm thick positioning flange 11. One side of the positioning flange 11 is provided with a central positioning pin 2 and a first connecting positioning hole 3, and the other side is provided with a clamping part 1. The positioning flange 11 is provided with multiple connecting holes 4, and the length of the clamping part 1 is not less than 100mm.

[0044] Step S2: Elevate the workpiece 14 and place it near the center of rotation of the horizontal machining center, such as... Figure 3As shown, an A1.5 / 4 center hole 8 is made in the middle of a square process boss 13 reserved at one end of the workpiece blank along the long end direction. At the other end, a positioning reference surface 12, a positioning hole, and three M10X15mm locking thread holes 7 are reserved at the end of the tooling interface position. The positioning hole includes one φ10H7X15mm main positioning hole 5 and one φ10H7X8mm second connecting positioning hole 6 with an M8X5 thread at the bottom. The process boss 13, the center hole 8, and the main positioning hole 5 are coaxially positioned (the coaxiality should be manually corrected during the first piece processing).

[0045] Step S3, as follows Figure 4 As shown, the workpiece 14 to be processed is connected to the connecting fixture. The center positioning pin 2 of the connecting fixture is inserted into the main positioning hole 5 of the workpiece blank. The first connecting positioning hole 3 is aligned with the second connecting positioning hole 6 of the workpiece blank and a shaft bolt is locked in. At the same time, the connecting hole 4 is aligned with the locking thread hole 7 and an M10 bolt is locked in, so that the six degrees of freedom of the workpiece 14 to be processed are completely restricted.

[0046] Step S4: Use the four-axis chuck of the vertical four-axis machining center to clamp the clamping part 1 of the connecting fixture. The clamping length is 50mm (distance from the chuck tip to the end face of the fixture). The origins of the Y and Z axes of the vertical four-axis machining center are placed on the center line of the clamping part of the connecting fixture, and the origin of the X axis is placed on the machining reference surface in step S3. Insert the center of the vertical four-axis machining center into the center hole 8, and use a dial indicator to correct the runout of the workpiece 14 to ensure that the runout of the workpiece 14 is less than 0.03mm. Then, perform rough machining on the four surfaces of the workpiece 14 (top, bottom, left, and right), leaving a 1mm allowance on each surface (i.e., leave a 1mm allowance in the normal direction of the workpiece 14).

[0047] Step S5: Keeping the clamped state unchanged, release the tip and then tighten the tip again.

[0048] Step S6: Recalibrate the X-axis origin and verify the runout of the workpiece 14 relative to the clamping part 1. If there is a large runout that fails to meet the machining accuracy requirements, the connecting fixture and the workpiece 14 need to be clamped together on the lathe, and the center hole needs to be recalibrated using the lathe tailstock. After completion, return it to the vertical four-axis machining center for further machining.

[0049] Step S7: Perform finishing on the top, bottom, left and right sides of the workpiece 14. Except for the position of the process chuck, all surfaces and holes are machined to the final dimensions.

[0050] Step S8: Remove the workpiece 14 to be processed, remove the tooling, use the maximum plane of the workpiece 14 to be processed for positioning, and use a vertical machining center to remove the process boss 13 and the positioning reference surface 12 on the workpiece 14 to be processed.

[0051] Step S9: The fitter grinds and removes the tool attachment at the chuck position of the workpiece 14 and polishes the surface of the workpiece 14.

[0052] This invention discloses a machining method for a small landing gear torque arm, primarily used for machining landing gear torque arm parts that are small in size, require smaller cutting tools, and have features on each surface that need machining, especially applicable to machining precision-sized mating surfaces. Through extensive testing and verification, this process method ensures the surface quality and accuracy of the small landing gear torque arm, maintains a stable machining process, and achieves high machining efficiency. It solves the problems of low machining efficiency, fragmented processes, and poor surface quality in small landing gear torque arms. This connecting fixture can also be adapted to the machining of other similar parts and other materials.

[0053] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can make many possible variations and modifications to the technical solution of the present invention, or modify it into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention should fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method of machining a small landing gear torque arm, characterized by It comprises the following steps: Step S1: based on the material of the workpiece, the size of the shape, the structural features, the reserved tooling interface position and the interface form in the process design, make the connecting tooling; Step S2: using horizontal machining center to make the tailstock hole at one end of the workpiece in the long end direction, and make the positioning reference surface, positioning hole and locking thread hole at the other end; Step S3: using the connecting tooling to connect the positioning reference surface, positioning hole and locking thread hole of the workpiece, so that the freedom of each direction of the workpiece blank is completely limited; Step S4: using the four-axis chuck of the vertical four-axis machining center to clamp the clamping part of the connecting tooling, and placing the Y and Z axis origins of the vertical four-axis machining center on the center line of the clamping part of the connecting tooling, placing the X axis origin on the positioning reference surface of the workpiece, and making the tailstock of the vertical four-axis machining center enter the tailstock hole to correct the runout of the workpiece, so that the runout of the workpiece is less than 0.03mm, and then rough machining the upper, lower, left and right four surfaces of the workpiece blank, leaving 1mm allowance on the surfaces; Step S5: keeping the clamping state of the workpiece unchanged, loosening the tailstock of the vertical four-axis machining center, and then re-tightening the tailstock; Step S6: re-correcting the X axis origin of the workpiece, and verifying the runout of the workpiece relative to the clamping part; Step S7: finishing all the surfaces of the workpiece, and machining all the surfaces and holes to the final product size of the workpiece except the process chuck position; Step S8: removing the workpiece and the connecting tooling, using the shape of the workpiece to position, and using the vertical machining center to remove the process chuck; Step S9: polishing the tool engagement position of the process chuck by the bench worker, and polishing the surface of the workpiece; One end of the workpiece is reserved with a process boss (13), the center of the process boss is provided with the tailstock hole (8), the other end of the workpiece is provided with the positioning reference surface (12), the main positioning hole (5), the second connecting positioning hole (6) and the locking thread hole (7), and the process boss, the tailstock hole and the main positioning hole are coaxial; The connecting tooling comprises a positioning flange (11), one side of the positioning flange is provided with a center positioning pin (2) matched with the main positioning hole, a first connecting positioning hole (3) matched with the second connecting positioning hole, the other side is provided with a clamping part (1), and a plurality of connecting holes (4) matched with the locking thread holes are arranged on the positioning flange.

2. The method of claim 1, wherein, The length of the clamping part is not less than 100mm.

3. The method of claim 1, wherein, In step S6, if the X axis origin of the workpiece has large runout and cannot meet the machining precision requirement, the connecting tooling and the part need to be clamped into the lathe together, and the tailstock of the lathe is used to re-correct the tailstock hole.

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