Processing method of aviation hydraulic system flat nozzle

Abstract

The present application relates to the field of aviation flat nozzle processing, and particularly relates to a kind of aviation hydraulic system flat nozzle processing method, and its specific steps are as follows: S1, the current situation of the analysis of pipe flaring is generated, the position of flat nozzle part turning tool mark and the stress concentration distribution generated in assembly;S2, select a reasonable processing method and calculate;Through the control of flat nozzle part turning surface tool mark position, assembly and reduction measures, structure size and processing mode, improve the processing control method of flat nozzle part, change the appearance of tool mark position, make the fatigue performance of pipe poor in assembly, and lay a foundation for the in-depth study of aviation flat nozzle part processing.

Description

Technical Field

[0001] This invention relates to the field of aerospace flat nozzle machining, specifically a machining method for aerospace hydraulic system flat nozzles. Background Technology

[0002] Flat nozzles are crucial components for connecting hydraulic pipelines. Due to uncertainties such as vibration and turbulence during aircraft flight, vibrations can occur between the tool marks on the flat nozzle and the outer wall of the conduit. This vibration causes stress concentration, leading to cracks in the conduit, hydraulic oil leakage, pressure reduction, and potential safety accidents. To address these issues, the machining method for flat nozzles has been redesigned. Even in harsh environments with high vibration, the tool marks on the machined surface of the flat nozzle mate with the conduit without causing stress concentration and wear.

[0003] In the aviation industry, the aircraft hydraulic system is a critical component of the aircraft and one of the important factors determining its performance and safety. The nozzle and guide tube are important parts of the hydraulic system, operating in harsh environments such as high vibration. The tool marks on the machined surface of the nozzle and its fit with the guide tube directly affect the service life of the hydraulic system and the safety of aircraft flight.

[0004] Numerous failure analyses of hydraulic systems have shown that, in cases of conduit failure in aircraft hydraulic systems, the primary cause is fatigue failure resulting from stress concentration at the interface between the nozzle and the conduit.

[0005] The turning process must take into account the tool marks that may appear on the surface of the part. Tool marks are mainly affected by factors such as the location of the tool contact and the machining method. Summary of the Invention

[0006] To address the aforementioned problems, this invention proposes a method for processing flat nozzles in aviation hydraulic systems.

[0007] A method for machining a flat nozzle for an aviation hydraulic system, the specific steps of which are as follows:

[0008] S1. Analyze the current status of conduit flaring, the location of machining marks on flat nozzle parts, and the stress concentration distribution during assembly, specifically including:

[0009] S11. The machined surfaces of the flat nozzle include end face one and end face two during machining, the position where the tool marks are generated on end face one and end face two, and the clearance fit between the outer diameter of the guide tube and the inner hole of the flat nozzle.

[0010] S12. During the flaring process, the conical surface of the guide tube is squeezed and plastically deformed, causing material to accumulate at the rounded corners. The distance from the material accumulation point to the end face of the guide tube is T.

[0011] S13. The locations of tool marks appearing in the two typical processing methods of the current flat pipe nozzle are different, and there are two specific methods for setting them.

[0012] S2. Select a suitable processing method and perform calculations:

[0013] S21. The flat nozzle is clamped twice during processing. The first clamping is the inlet toolpath, and the second clamping is the outlet toolpath.

[0014] S22. The second clamping generates a runout δ. The flat nozzle outlet tool path R is connected to the inlet tool path inner hole D by a straight line at an angle β, that is, the tool mark is C3, and the distance from C3 to the end face is E.

[0015] In step S1, the flat nozzle and the guide tube are assembled, and during the assembly process, the inner conical surface of the flat nozzle and the outer conical surface of the guide tube are matched.

[0016] The processing method of step S13 is to follow the tool path of the flat nozzle fillet R and the flat nozzle inner hole D, and the tool mark is C1.

[0017] The second method of step S13 is the tool path at the junction of the tool mark C2 and the inner hole D of the flat nozzle, with the tool mark being C2.

[0018] The method described above involves a tool mark C1 fitting with a conduit. The outer diameter P1 of the conduit material accumulation area is larger than the inner diameter D of the flat nozzle. During assembly, the material accumulation area at the root of the conduit transitions to the tool mark of the flat nozzle, resulting in line-to-surface contact and stress concentration. Consequently, cracks appear at the material joint of the conduit's outer diameter.

[0019] The method described above involves connecting the knife mark C2 with the conduit, sealing and fixing the flat nozzle and conduit together. The vibration source first vibrates through the conduit. In the entire assembly area of ​​the flat nozzle and conduit, the point with the largest vibration amplitude is the end face of the inner hole D of the flat nozzle and the conduit at that point.

[0020] During the vibration of the conduit, the outer diameter of the conduit comes into contact with or collides with the cutting mark C2 of the flat nozzle, causing stress concentration at the outer end face of the conduit and resulting in cracks on the end face of the conduit.

[0021] The specific calculation for step S22 is as follows:

[0022] When P1 = (P + 2δ) and (δ = (DP) / 2), the inner hole of the flat nozzle is completely fitted with the outer diameter of the material accumulation area of ​​the conduit, and the other end is a clearance fit;

[0023] When P1>(P+2δ) and (δ>(DP) / 2), the fillet material stacking length T>(E+Q) of the conduit is surface-line mating, and stress concentration will occur in the conduit during assembly.

[0024] When T < (E + Q), with surface-to-surface fit, stress concentration will not occur during the assembly of the conduit;

[0025] When P1 < (P + 2δ) and (δ < (DP) / 2), the catheter and the flat nozzle are fitted with a clearance.

[0026] The beneficial effects of this invention are: by controlling aspects such as the location of tool marks on the machined surface of aviation fuel system flat nozzle parts, assembly and reduction measures, structural dimensions and processing methods, the processing control method of flat nozzle parts is improved, the morphology of tool marks is changed, and the poor fatigue performance of the guide tube during assembly is reduced, laying the foundation for in-depth research on the processing of aviation flat nozzle parts. Attached Figure Description

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] Figure 1 This is a schematic diagram of the machined surface of the flat nozzle of the present invention;

[0029] Figure 2 This is a schematic diagram of the assembly of the flat nozzle and the guide tube according to an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram illustrating the plastic deformation of the catheter flare in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the tool path of the flat pipe nozzle joint tool mark C1 in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the tool path of the flat pipe nozzle joint tool mark C2 in an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the tool path and tool mark C3 of the novel processing method for flat nozzles according to an embodiment of the present invention.

[0034] Figure 7 This is a schematic diagram of the assembly of the flat nozzle with the knife mark C3 and the guide tube according to an embodiment of the present invention.

[0035] Figure 8 This is a flowchart illustrating the assembly analysis process for an embodiment of the present invention. Detailed Implementation

[0036] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below.

[0037] like Figures 1 to 8 As shown, a method for machining a flat nozzle of an aviation hydraulic system includes the following specific steps:

[0038] S1. Based on the part dimensions, structure, and assembly characteristics, analyze the current status of the flaring of guide tube 2, the location of the machining tool marks on the flat nozzle 1, and the stress concentration distribution during assembly, specifically including:

[0039] S11. The machined surfaces of the flat nozzle 1 include end face c and end face d during machining, the position where the tool marks are generated by end face c and end face d, and the clearance fit between the outer diameter P of the guide tube 2 and the inner hole D of the flat nozzle 1.

[0040] S12. During the flaring process, the conical surface of the guide tube 2 is squeezed and plastically deformed, causing material to accumulate at the rounded corner. The distance from the material accumulation point 3 to the end face of the guide tube 2 is T.

[0041] S13. The locations of the tool marks that appear in the two typical processing methods of the current flat tube nozzle 1 are different, and there are two specific methods for setting them.

[0042] S2. Select a reasonable processing method and perform calculations to avoid stress concentration fatigue on the surface of conduit 2 due to tool marks during assembly, which could lead to cracking failure of conduit 2.

[0043] S21, flat nozzle 1 is clamped twice during processing. The first clamping is the inlet toolpath, and the second clamping is the outlet toolpath.

[0044] S22. The second clamping generates a runout δ. The exit toolpath R of the flat nozzle 1 is connected to the inner hole D of the inlet toolpath by a straight line at an angle β, that is, the tool mark is C3, and the distance from C3 to the end face is E.

[0045] By controlling aspects such as the location of tool marks on the machined surface of flat nozzle parts of aviation fuel systems, assembly and reduction measures, structural dimensions and machining methods, the machining control methods of flat nozzle parts are improved, the morphology of tool marks is changed, and the poor fatigue performance of the guide tube during assembly is reduced, laying the foundation for in-depth research on the machining of aviation flat nozzle parts.

[0046] In the figure, label 4 represents the flaring tool, label 5 represents the exit toolpath trajectory, label 6 represents the theoretical trajectory, and label 7 represents the inlet toolpath trajectory.

[0047] The processing method of step S13 is to follow the tool path of the fillet R of the flat nozzle 1 and the inner hole D of the flat nozzle 1, and the tool mark is C1.

[0048] The second method of step S13 is the tool path where the tool mark position C2 is at the junction of the flat nozzle 1r and the inner hole D of the flat nozzle 1, and the tool mark is C2.

[0049] In step S1, the flat nozzle 1 and the conduit 2 are assembled. During the assembly process, the inner conical surface of the flat nozzle 1 and the outer conical surface of the conduit 2 cooperate to ensure the sealing of the pipeline.

[0050] The method described above involves a joint mark C1 that mates with the conduit 2. The outer diameter P1 of the material accumulation area 3 of the conduit 2 is larger than the inner diameter D of the flat nozzle 1. During assembly, the material accumulation area 3 at the root of the conduit 2 and the joint mark of the flat nozzle 1 are in transitional fit and contact with each other. During pipeline vibration, stress concentration occurs, causing cracks to appear at the material joint of the outer diameter of the conduit 2.

[0051] The method described in section 2 involves the connection of the knife mark C2 with the conduit 2, and the flat nozzle 1 and the conduit 2 are sealed and relatively fixed. The vibration source first vibrates through the conduit 2. In the entire assembly area of ​​the flat nozzle 1 and the conduit 2, the point with the largest vibration amplitude is the end face of the inner hole D of the flat nozzle 1 and the conduit 2 at that point.

[0052] During the pipeline vibration, the outer diameter of the conduit 2 comes into contact with or collides with the joint mark C2 of the flat nozzle 1, causing stress concentration at the outer end face of the conduit 2 and resulting in cracks on the end face of the conduit 2.

[0053] The specific calculation for step S22 is as follows:

[0054] When P1 = (P + 2δ) and (δ = (DP) / 2), the inner hole of the flat nozzle 1 is completely fitted with the outer diameter of the material accumulation area 3 of the guide tube 2, and the other end is a clearance fit;

[0055] When P1>(P+2δ) and (δ>(DP) / 2), the fillet material stacking length T>(E+Q) of the conduit 2 is fused with the surface line, and the conduit (2) will generate stress concentration during the assembly process;

[0056] When T < (E + Q), with surface-to-surface fit, no stress concentration will occur in conduit 2 during assembly;

[0057] When P1 < (P + 2δ) and (δ < (DP) / 2), the catheter 2 and the flat nozzle 1 are fitted with a clearance.

[0058] The flat nozzle of model HB4-44FB2-8 from the HB4-44-2002 standard was selected for test analysis. The flat nozzle and guide tube were used for assembly tests, and the dimensions are shown in Table 1.

[0059]

[0060]

[0061] In tests 1-3 and 4-6, when T > (E+Q), the flat nozzle scratches the guide tube during the fitting process, resulting in stress concentration; when T < (E+Q), a bright extrusion ring appears on the outer diameter of the guide tube near the root r during assembly, indicating that the tool mark and the material accumulation area of ​​the guide tube do not contact each other during assembly, and no stress concentration occurs in the guide tube.

[0062] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely prisms of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method of machining a flat nozzle for an aircraft hydraulic system, the method comprising: The specific steps are as follows: ​ S1. Analyze the current status of the flaring of the guide tube (2), the location of the tool marks in the machining of the flat nozzle (1) and the stress concentration distribution during assembly, specifically including: S11, The machined surface of the flat nozzle (1) includes end face one (c) and end face two (d) during machining. The end face one (c) and end face two (d) produce tool marks. The outer diameter P of the guide tube (2) and the inner diameter D of the flat nozzle (1) are in clearance fit. S12. During the flaring process, the conical surface of the guide tube (2) undergoes plastic deformation due to compression, resulting in material accumulation at the rounded corner. The distance from the material accumulation point (3) to the end face of the guide tube (2) is T. S13. The tool marks appearing in the two typical processing methods of the flat nozzle (1) are different. There are two specific methods. The processing method one of step S13 is to walk the tool path from the rounded corner R of the flat nozzle (1) to the inner hole of the flat nozzle (1), and the tool mark is C1. The processing method two of step S13 is to walk the tool path from the root r of the flat nozzle (1) to the inner hole of the flat nozzle (1), and the tool mark is C2. S2. Select a suitable processing method and perform calculations: S21, Flat nozzle (1) is clamped twice during processing. The first clamping is the inlet toolpath trajectory, and the second clamping is the outlet toolpath trajectory. S22, the second clamping generates runout δ, the flat nozzle (1) outlet tool path R adopts a straight line with an angle of β to connect with the inner hole of the inlet tool path, that is, the tool mark is C3, and the distance from C3 to the end face is E; The specific calculation for step S22 is as follows: When P1 = (P + 2δ) and (δ = (DP) / 2), the inner hole of the flat nozzle (1) is completely fitted with the outer diameter of the material accumulation area (3) of the guide tube (2), and the other end is a clearance fit; When P1 > (P+2δ) and (δ > (DP) / 2), the fillet material stacking length T of the conduit (2) is greater than (E+Q), and the surface is fitted. Stress concentration will occur in the conduit (2) during the assembly process. When T < (E + Q), with surface-to-surface fit, the conduit (2) will not experience stress concentration during assembly; When P1 < (P+2δ) and (δ < (DP) / 2), the conduit (2) and the flat nozzle (1) are in clearance fit, where P1 is the outer diameter of the material accumulation point (3) of the conduit (2) and Q is the distance from the end face of the flat nozzle to the end face of the conduit after assembly.

2. The method of claim 1, wherein: In step S1, the flat nozzle (1) and the guide tube (2) are assembled. During the assembly process, the inner conical surface of the flat nozzle (1) and the outer conical surface of the guide tube (2) are engaged.

3. The method of claim 1, wherein: The method described above involves a joint mark C1 that fits with the conduit (2). The outer diameter P1 of the material accumulation area (3) of the conduit (2) is larger than the inner diameter D of the flat nozzle (1). During the assembly process, the material accumulation area (3) at the root of the conduit (2) and the joint mark of the flat nozzle (1) transition to fit, resulting in line-surface contact and stress concentration. Cracks appear at the material joint of the outer diameter of the conduit (2).

4. The method of claim 1, wherein: The method of the second joint is to fit the knife mark C2 with the conduit (2), the flat nozzle (1) and the conduit (2) are sealed and relatively fixed, the vibration source first vibrates through the conduit (2), and in the entire assembly area of ​​the flat nozzle (1) and the conduit (2), the vibration amplitude is the end face of the inner hole of the flat nozzle (1) and the conduit (2) at that point.

5. The method of claim 4, wherein: During the pipeline vibration of the conduit (2), the outer diameter of the conduit (2) comes into contact with or collides with the joint mark C2 of the flat nozzle (1), causing stress concentration at the outer end face of the conduit (2) and resulting in crack failure at the end face of the conduit (2).

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