Helicopter rotor system pendulum reducer aluminum alloy complex cylinder part machining method

Abstract

The application belongs to the field of mechanical processing and relates to a processing method of an aluminum alloy complex cylinder part of a helicopter rotor system pendulum eliminator. The method comprises the following steps: distributing the processing allowance of a forging blank, transferring a locating datum from the forging blank to a standard base plate of the locating datum, clamping the forging blank on the standard base plate provided with the locating datum; processing the locating datum so that the processed locating datum becomes a positioning datum of rough processing; rough processing a center inner hole of the forging blank according to the positioning datum of rough processing; clamping and rough processing a special mandrel and a core shaft, and rough processing a fork and a positioning hole of the forging blank; installing the positioning hole of the rough processed forging blank and the positioning datum of rough processing in cooperation with a special lathe tooling, and finishing the center inner hole; clamping and finishing the special mandrel and the core shaft, and finishing the fork and the drilling of the forging blank.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of mechanical processing, and relates to a processing method for an aluminum alloy complex cylinder part of a helicopter rotor system pendulum damper. BACKGROUND

[0002] The pendulum damper is a key component in the helicopter rotor system, which can provide sufficient stiffness and damping for the pendulum motion of the helicopter blade, so as to suppress the ground and air resonance of the helicopter, thereby improving the stability of the helicopter. The outer cylinder of the pendulum damper is a complex cylinder part taking an aluminum alloy forging as a blank, and is the most important component part of the pendulum damper. The existing processing method for the part adopts handwork of turners, milling workers and fitters, and needs to be repeatedly transferred between the above work types in the processing process, so that the processing cycle is long, and the processing quality is unstable. SUMMARY

[0003] The application aims to provide a stable and efficient processing method for an aluminum alloy complex cylinder part.

[0004] TECHNICAL SOLUTION

[0005] The application provides a processing method for an aluminum alloy complex cylinder part of a helicopter rotor system pendulum damper, which comprises the following steps.

[0006] The processing allowance of the forging blank is distributed, the locating datum is transferred from the forging blank to a standard base plate with the locating datum, and the forging blank is clamped on the standard base plate with the locating datum.

[0007] The locating datum is processed, so that the processed locating datum becomes a positioning datum for rough machining.

[0008] According to the positioning datum for rough machining, the center inner hole of the forging blank is roughly machined.

[0009] The special mandrel clamping and rough machining mandrel are adopted to roughly machine the fork mouth and positioning hole of the part blank.

[0010] The positioning hole of the forging blank after rough machining and the positioning datum after rough machining are matched and installed with the special lathe tooling to precisely machine the center inner hole.

[0011] The special mandrel clamping and precise machining mandrel are adopted to precisely machine the fork mouth and drilling hole of the forging blank.

[0012] Further, the method further comprises the following steps.

[0013] The thread hole is machined, honed, dimensionally detected, fluorescently detected, and anodized.

[0014] Further, the processing allowance of the forging blank is distributed, the locating datum is transferred from the forging blank to a standard base plate with the locating datum, and the forging blank is clamped on the standard base plate with the locating datum.

[0015] The machining allowance of the forging blank is checked by means of laser scanning or visual identification, etc., to ensure that the minimum radial machining allowance is not less than 0.2 mm; then the forging blank is clamped on a standard base plate provided with a locating reference, and the position relationship between the forging blank and the locating reference is determined again by means of laser scanning.

[0016] Further, the locating reference is machined, including:

[0017] According to the position relationship between the forging blank and the locating reference, the locating reference is machined.

[0018] Further, the center hole of the forging blank is roughly machined according to the locating reference, including:

[0019] The center hole of the rough machining part is machined to a size d0 +0.03 with a dimensional accuracy and a roughness R a 3.2. The hole end face is machined to ensure that the perpendicularity of the end face to the center hole axis is 0.005 mm, and a machining allowance of 1 mm is left after machining;

[0020] At the same time, the axial positioning plane is machined.

[0021] Further, the special mandrel clamping includes: a center positioning mandrel, a pressing mechanism, a high base, and an axial positioning device.

[0022] The center positioning mandrel is a rough machining mandrel or a finish machining mandrel; the center positioning mandrel is installed on the high base, the forging blank is sleeved on the center positioning mandrel through the rough machining center hole, and the lower end face of the forging blank is pressed against the high base by the pressing mechanism; the axial positioning device is installed on the high base and cooperates with the rough machining locating reference to realize axial positioning.

[0023] The special mandrel clamping and the rough machining mandrel are used to roughly machine the fork of the forging blank and to make a positioning hole, including:

[0024] The special mandrel clamping suitable for a five-coordinate numerical control milling machine is used to roughly machine the fork, and a machining allowance of 1 mm is left after rough machining; the positioning hole is made at the radial hole of the forging blank, and the positioning hole needs to ensure a dimensional accuracy H9 and a roughness R a 1.6.

[0025] Further, the special lathe tooling includes: an adapter disc, a counterweight, a pressing mechanism, a clamping body, a positioning pin, a center height adjusting mechanism, and a directional pin.

[0026] The one end of the clamp body is connected with the spindle interface of the numerical control lathe through the adapter disc, and a counterweight is also installed; the other end of the clamp body is provided with a center height adjusting mechanism on the upper end face, the center height adjusting mechanism is provided with a positioning pin and a directional pin, the forged blank is horizontally placed on the center height adjusting mechanism, and the positioning pin and the directional pin are positioned in cooperation with the rough machining positioning hole;

[0027] The rough machining positioning hole and the rough machining positioning reference of the forged blank are installed in cooperation with the special lathe tooling, the center inner hole is finished, and the center inner hole is finished.

[0028] The special lathe tooling is used to clamp the part on the spindle of the numerical control lathe, and the center hole of the part is finished, and the machining size is D0 +0.03 , and 0.05mm honing allowance is left after finishing, so that the roughness R a 16.

[0029] Further, the special spindle is used to clamp and finish the fork and the drilling hole of the forged blank, and the special spindle is used to clamp and finish the fork and the drilling hole of the forged blank.

[0030] The special spindle suitable for the five-coordinate numerical control milling machine is used for clamping, and the contour of the fork and the bushing hole are finished by one positioning; when the bushing installation hole of the fork is machined, the machining is completed from one side of the fork at one time, the center positioning spindle is matched with the center hole size D +0.03 0 with a gap of 0.03-0.05mm;

[0031] At the same time, the hydraulic holes are drilled, the finish machining of the hole positioning surface is completed before drilling the hydraulic holes, then the center drill is used to drill the guide hole, and finally the special hard alloy step drill is used to complete the machining of the step hole and the hole chamfer at one time.

[0032] Advantages:

[0033] The present application is directed to the machining process of aluminum alloy complex cylindrical parts, and innovatively proposes to use a five-axis numerical control machine tool to complete the rough machining of the center positioning hole and the axial positioning plane in one clamping, which greatly improves the dimensional accuracy and form and position accuracy of the positioning reference, and improves the reliability of positioning; innovatively proposes a spindle tool suitable for numerical control lathes, which realizes the machining of all structural dimensions of the center hole of the part using the same positioning reference, ensuring the dimensional accuracy and coaxiality requirements; innovatively proposes a mandrel suitable for five-coordinate numerical control milling machines, which realizes the machining of the fork contour, the bushing mounting hole and each hydraulic hole in one clamping, effectively ensuring the form and position tolerance requirements of the part; innovatively proposes to use a special hard alloy step drill to complete the machining of the step hole and the hole chamfer in one time, which greatly reduces the number of tools in the hole machining process and improves the concentricity of the step hole; through the above technical solutions, the part machining process is basically numerically controlled, and the number of machining turns is greatly reduced, the machining efficiency is significantly improved, and high-quality and efficient machining of aluminum alloy complex cylindrical parts is realized. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a flowchart of the present application.

[0035] Figure 2 is a structural schematic diagram of a special mandrel of a five-coordinate numerical control milling machine.

[0036] Figure 3 is a structural schematic diagram of a lathe spindle tool. DETAILED DESCRIPTION

[0037] The present application provides an aluminum alloy complex cylindrical part machining method, as shown in Figure 1 , comprising:

[0038] Step 1, residual amount distribution.

[0039] Step 2, rough machining positioning reference.

[0040] Step 3, rough machining of the center hole.

[0041] Step 4, rough machining of the fork and positioning hole.

[0042] Step 5, fine machining of the center hole.

[0043] Step 6, fine machining of the fork and drilling.

[0044] Step 7, thread hole.

[0045] Step 8, honing.

[0046] Step 9, size detection.

[0047] Step 10, fluorescent penetrant testing.

[0048] Step 11, anodizing.

[0049] Step 1 is specifically: using laser scanning or visual recognition and other ways to check the machining allowance of the forging blank, to ensure that the minimum radial machining allowance is not less than 0.2mm; then the part blank is clamped on the standard base plate equipped with the alignment reference, and the position relationship between the part and the alignment reference is determined again by laser scanning, and the to-be-made coarse reference should be ensured to be accessible in step 2.

[0050] Step 2 is specifically: after the position relationship between the part and the alignment reference is determined in step 1, the part is machined to the coarse machining positioning reference.

[0051] Step 3 is specifically that the size precision of the coarse machining center hole of the part is d +0.03 0, the roughness is Ra3.2, the hole end face is machined, the perpendicularity of the end face to the center hole axis is ensured to be 0.005mm, and the machining allowance is 1mm after machining. At the same time, the axial positioning plane is machined.

[0052] Step 4 is specifically: using a specially designed spindle suitable for a five-coordinate numerical control milling machine to clamp and coarsely machine the forked mouth shape, leaving a machining allowance of 1mm after coarse machining. A positioning hole is made at the radial hole of the part, and the positioning hole needs to ensure the size precision H9 and the roughness Ra1.6. A finishing allowance of 0.5mm is left at the positioning hole. The specially designed spindle suitable for a five-coordinate numerical control milling machine is shown in Figure 2 , wherein 1 is a center positioning spindle, 2 is a pressing mechanism, 3 is a raised base, and 4 is an axial positioning device. The size of the center positioning spindle 1 should ensure that the fit clearance with the center hole size d +0.03 0 is 0.03-0.05mm, and the outer shape size of the raised base 3 needs to be determined according to the spindle size of the machining equipment and the stroke of each shaft.

[0053] Step 5 is specifically: using a specially designed lathe tooling, the part is clamped on the spindle of the numerical control lathe, and the part center hole is finished machined, the machining size is D0 +0.03 , a honing allowance of 0.05mm is left after finishing machining, and the roughness is ensured to be Ra16, and the specially designed tooling is shown in Figure 3 , wherein 1' is an adapter disc, 2' is a counterweight, 3' is a pressing mechanism, 4' is a clamp body, 5' is a positioning pin, 6' is a center height adjusting mechanism, and 7' is a directional pin. The adapter disc 1' needs to be designed according to the interface form of the selected numerical control lathe spindle, the counterweight 2' is used to adjust the center of gravity of the clamp, the positioning pin 5' and the directional pin 7' need to cooperate with the positioning hole made in step 4, the size precision is f6, and the roughness is Ra0.8. The positioning hole is a cylindrical pin, and the directional pin is a rhombic pin;

[0054] Step 6: The special mandrel is used to clamp the five-coordinate numerical control milling machine, and the contour of the fork and the bushing hole are finished at one time. The bushing installation hole of the fork should be machined from one side of the fork at one time. The special mandrel is consistent with the requirement of step 4. The center positioning mandrel 1 is consistent with the center hole size D +0.03 0 fit clearance 0.03-0.05mm. At the same time, drill the hydraulic holes. Before drilling the hydraulic holes, the precision machining of the orifice positioning surface should be completed first. Then, the guide hole is drilled with a center drill. Finally, the special hard alloy step drill is used to complete the machining of the step hole and the orifice chamfer at one time.

[0055] Step 7: The corresponding size of the tap is used to complete the machining of the thread hole;

[0056] Step 8: The honing and special honing oil stone are used to super-finish the center hole of the part. The machining amount is not more than 0.05mm, and the roughness Ra0.32 is ensured;

[0057] Step 9: The inside micrometer is used to check the size of each hole, and the three-coordinate measuring instrument is used to check the coaxiality, perpendicularity, parallelism and other form and position tolerances;

[0058] Step 10: The surface micro-cracks of the part are detected by using fluorescent detection method to ensure the fatigue performance requirement of the part;

[0059] Step 11: The inner and outer surfaces of the part are subjected to chromic acid anodization to improve the corrosion resistance of the part.

Claims

1. A method for machining complex cylindrical aluminum alloy parts for a helicopter rotor system oscillation damper, characterized in that, include: The machining allowance for the forging blank is allocated by transferring the alignment datum from the forging blank to the standard base plate of the alignment datum, and the forging blank is clamped on the standard base plate equipped with the alignment datum. The machining alignment datum is used to make the aligned datum after machining the positioning datum for rough machining. Based on the positioning datum for rough machining, the center inner hole of the forging blank is rough machined; It uses a specially designed mandrel clamping and rough-machined mandrel to rough-machine the fork and positioning hole of the workpiece blank; The rough-machined forging blank positioning holes and rough-machined positioning datum are fitted with a special lathe tooling and installed to finish the center inner hole; Special mandrel clamping and precision-machined mandrel are used to precision machine the fork and drill holes of the forging blank; The specially designed mandrel includes: a center positioning mandrel, a clamping mechanism, a raised base, and an axial positioning device; The center positioning mandrel is either a rough-machined mandrel or a fine-machined mandrel; the center positioning mandrel is installed on the raised base, and the forging blank is fitted onto the center positioning mandrel through its own rough-machined center hole. The clamping mechanism presses the lower end face of the forging blank against the raised base; the axial positioning device is installed on the raised base and cooperates with the rough-machined positioning datum to achieve axial positioning. Using a specially designed mandrel clamping and rough-machined mandrel, the fork and positioning hole of the rough-machined workpiece blank include: Using a specially designed mandrel suitable for a five-axis CNC milling machine, the fork opening is rough-machined, leaving a 1mm machining allowance. Positioning holes are then drilled at the radial holes of the forging blank. These positioning holes must ensure a dimensional accuracy of H9 and a surface roughness of R. a 1.6; The specially designed lathe tooling includes: a transfer plate, a counterweight, a clamping mechanism, a fixture body, a locating pin, a center height adjustment mechanism, and a directional pin; One end of the fixture is connected to the CNC lathe spindle interface via an adapter plate, and a counterweight is also installed thereon. The upper surface of the other end of the fixture is equipped with a center height adjustment mechanism, which is equipped with a positioning pin and a directional pin. The forging blank is placed horizontally on the center height adjustment mechanism, and the positioning pin and the directional pin are positioned in conjunction with the positioning holes machined in the roughing process. A clamping mechanism is installed on the fixture to clamp the forging blank onto the center height adjustment mechanism. The rough-machined forging blank positioning holes and rough-machined positioning datum are fitted with a specially designed lathe tooling for finishing the center inner hole, including: Using a specially designed lathe fixture, the part is clamped on the spindle of a CNC lathe, and the center hole of the part is precision machined to a dimension of [missing value]. After finishing, leave a honing allowance of 0.05mm to ensure surface roughness R. a 1.

6.

2. The processing method according to claim 1, characterized in that, The method also includes: threading holes, honing, dimensional inspection, fluorescent flaw detection, and anodizing.

3. The processing method according to claim 1, characterized in that, The allocation of machining allowance for the forging blank involves transferring the alignment datum from the forging blank to a standard base plate containing the alignment datum. The forging blank is clamped on the standard base plate containing the alignment datum, including: Use laser scanning or visual recognition to check the machining allowance of the forging blank, and ensure that the minimum radial machining allowance is not less than 0.2mm; The forging blank is then clamped on a standard base plate equipped with a datum, and the positional relationship between the forging blank and the datum is determined again by laser scanning.

4. The processing method according to claim 3, characterized in that, The machining alignment benchmark includes: Based on the positional relationship between the forging blank and the alignment datum, the positioning datum is machined and aligned to obtain the rough-machined positioning datum.

5. The processing method according to claim 4, characterized in that, Based on the positioning datum for rough machining, the central inner hole of the rough-machined forging blank includes: Center hole dimensions of rough-machined parts Dimensional accuracy, surface roughness R a 3.2 Machining the end face of the hole, ensuring that the perpendicularity of the end face to the axis of the center hole is 0.005mm, and leaving a machining allowance of 1mm in each place after machining; at the same time, completing the machining of the axial positioning plane.

6. The processing method according to claim 5, characterized in that, Using a specially designed mandrel clamp and precision-machined mandrel, the fork joints and holes of the forging blank are precision machined, including: Using a specially designed mandrel suitable for a five-axis CNC milling machine, the fork contour and bushing hole are precision machined in one operation. When machining the bushing mounting hole at the fork, the machining should be completed in one go from one side of the fork. The dimensions of the center positioning mandrel and the center hole are... The clearance between the parts is 0.03 to 0.05 mm. Meanwhile, hydraulic holes are drilled in various locations. Before drilling the hydraulic holes, the positioning surface of the hole opening needs to be finely machined first. Then, a guide hole is drilled using the center. Finally, a special carbide step drill is used to complete the machining of the step hole and the chamfer of the hole opening in one go.

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