CN-121992324-A - Maintenance method for reducing out-of-standard fault rate of aluminum element content of lubricating oil of aircraft engine accessory case

CN121992324ACN 121992324 ACN121992324 ACN 121992324ACN-121992324-A

Abstract

The invention relates to the technical field of aeroengine maintenance, and discloses a maintenance method for reducing the failure rate of exceeding the standard of the content of aluminum element in the lubricating oil of an accessory case of an aeroengine, so as to reduce the failure rate of exceeding the standard of the content of aluminum element in the lubricating oil of the accessory case of the aeroengine; the method comprises the following steps of 1) determining a corresponding area of the aluminum bushing to be reinforced processed as a laser impact strengthening area according to an easy abrasion area of the aluminum bushing of the accessory case to be maintained, and setting machining allowance, 2) determining a deformation control area and machining allowance of the aluminum bushing to be reinforced processed, 3) carrying out laser impact strengthening pretreatment on the aluminum bushing to be reinforced, and 4) carrying out laser impact strengthening on the laser impact strengthening area of the aluminum bushing to be reinforced.

Inventors

XU LIANGHUI
YAN ZIHAN
DUAN WENTAO
ZHOU QUN
Miao Guolei
CHEN TAILI
LUO KUILIN
LUO PAN
ZHAO HU
HOU CHAOSHAN
YANG BIN

Assignees

成都天翔动力技术研究院有限公司

Dates

Publication Date: 20260508
Application Date: 20260212

Claims (8)

1. A maintenance method for reducing the failure rate of exceeding the standard of the content of aluminum element in lubricating oil of an accessory case of an aeroengine is characterized by comprising the following steps: 1) According to the easy-abrasion area of the aluminum bushing of the accessory case to be maintained, determining the corresponding area of the aluminum bushing to be reinforced and processed as a laser impact reinforced area, and setting machining allowance; 2) Determining a deformation control area and machining allowance of the aluminum bushing to be reinforced; 3) Performing laser shock peening pretreatment on the aluminum bushing to be machined in a reinforced mode; 4) And carrying out laser shock peening on a laser shock peening area of the aluminum bushing to be reinforced.
2. The maintenance method for reducing the exceeding failure rate of the content of aluminum element in the lubricating oil of the accessory case of the aeroengine according to claim 1, wherein the step 1) comprises the following specific steps: 1.1 Taking down an accessory case with exceeding aluminum content of lubricating oil of the aeroengine, decomposing the accessory case, taking down all aluminum bushings, analyzing abrasion marks of the taken down aluminum bushings, and determining an easily-abraded area of the aluminum bushings; 1.2 Setting the corresponding easy-abrasion area of the aluminum bushing to be reinforced as a laser shock strengthening area, and setting machining allowance for the laser shock strengthening area.
3. The maintenance method for reducing the over-standard failure rate of the content of aluminum element in the lubricating oil of the accessory case of the aeroengine according to claim 1 is characterized in that the step 2) is specifically to determine that the inner ring strengthening surface, the outer diameter and the mounting edges of the two end surfaces are deformation control areas of the aluminum bushing to be strengthened, and the machining allowance of each part is as follows: 2.1 Setting the allowance of the strengthening surface of the inner ring to be consistent with the machining allowance of the laser shock strengthening area; 2.2 Setting the reserved allowance of the outer diameter to be more than or equal to the final delivery size of the outer side to be +3mm; 2.3 The reserved allowance of the installation edges of the two end surfaces is more than or equal to the target thickness of the installation edges and is +1mm.
4. The maintenance method for reducing the failure rate of exceeding the standard of the content of aluminum element in the lubricating oil of the accessory case of the aeroengine according to claim 1, wherein the step 3) comprises the following steps: 3.1 Treating the surface of the inner ring of the aluminum bushing to be reinforced and processed to ensure that the roughness is less than or equal to Ra0.3mu m, and cleaning the reinforcing surface of the inner ring by adopting an organic cleaning agent; 3.2 A metal foil adhesive tape or a black polymer adhesive tape protective layer is pasted on the laser shock strengthening area, so that no bubble exists between the protective layer and the pasting surface, and the coverage area of the protective layer is more than or equal to 2mm beyond the edge of the laser shock strengthening area.
5. The maintenance method for reducing the exceeding failure rate of the content of aluminum element in the lubricating oil of the accessory case of the aeroengine according to claim 1, wherein the step 4) comprises the following specific steps: 4.1 After the step 3), fixing the aluminum bush to be reinforced by adopting a deformation constraint clamp to form a deformation constraint clamp-aluminum bush combination, mounting the combination on a centering chuck clamp of processing equipment, enabling the axis of the aluminum bush to be reinforced to be parallel to the rotation axis of the centering chuck clamp, and enabling the axis deviation value of the axis of the aluminum bush to be reinforced to be less than or equal to phi 1.0mm; 4.2 A hierarchical laser shock strengthening path of the aluminum bushing to be strengthened and processed is planned; 4.3 Setting laser process parameters, namely setting the laser energy density of the aluminum alloy to be 4.25-5.66 GW/cm < 2 >, setting the laser energy density to be = (4.25-5.66 GW/cm < 2 >/cos theta > when the laser incidence angle theta is zero, setting the spot overlap ratio to be more than or equal to 50% when a round laser spot is adopted, setting the spot diameter to be 3-5 mm, and setting the pulse width to be 20ns, and setting the spot overlap ratio to be more than or equal to 10% when a square spot is adopted, and setting the spot side length to be 3-5 mm and the pulse width to be 20ns; 4.4 Performing laser shock peening on a single layer of the aluminum bushing to be reinforced, and removing the protective layer after the laser shock peening is completed; 4.5 And then repeating the steps 3), 4.1), 4.2), 4.3) and 4.4) until all the layers of the aluminum bushing to be reinforced are subjected to laser shock peening.
6. The maintenance method for reducing the exceeding failure rate of the content of aluminum element in the lubricating oil of the accessory case of the aeroengine according to claim 5, wherein the step 4.2) comprises the following specific steps: 4.2.1 According to the structural characteristics of the aluminum bushing, the central axis of the aluminum bushing is horizontal during laser shock reinforcement, the aluminum bushing is reinforced in a laser fixing and moving mode, and the direction of the aluminum bushing is adjusted to enable the 3 o 'clock or 9 o' clock direction of the aluminum bushing to be used as a reinforcing point; 4.2.2 Then calculating laser incidence angle theta=arctan (aluminum bushing width/aluminum bushing inner diameter) +5-10 degrees according to the three-dimensional model or drawing size of the aluminum bushing; 4.2.3 Setting the layering number of the laser shock strengthening area according to the lap ratio, calculating single-layer facula lattice quantity = 2 pi x laser shock strengthening internal diameter x 2/r ", wherein r is the laser facula diameter, adopting a column-by-column strengthening mode for the aluminum bush, rotating the aluminum bush by an angle after pulse laser light emergence, and carrying out strengthening of the next facula, wherein the rotating angle is calculated according to the formula of 'rotating angle = 360 DEG/(4 pi x laser shock strengthening internal diameter/r'; 4.2.4 The distance between the laser outlet and the strengthening point of the aluminum bushing is set, so that the laser spot size meets the preset strengthening requirement, the ultrapure water constraint layer is loaded at the position 3-8 mm above the strengthening point, and a uniform water film with the thickness of 1.5-2.5 mm is formed at the strengthening point under the action of gravity and inertia of the ultrapure water, and meanwhile, water drainage can be smoothly carried out.
7. The maintenance method for reducing the excessive failure rate of the aluminum element content of the lubricating oil of the accessory case of the aeroengine according to any one of claims 1 to 6, further comprising the step 5) of sending the aluminum bushing to be reinforced to a machining process after the laser shock peening is completed, removing the machining allowance reserved in the deformation control area of the aluminum bushing to be reinforced, and obtaining the reinforced aluminum bushing by machining until the aluminum bushing reaches the final delivery size.
8. The maintenance method for reducing the excessive failure rate of the content of aluminum elements in the lubricating oil of the accessory case of the aeroengine according to claim 7 is characterized by further comprising the step 6) of assembling the reinforced aluminum bushing with the accessory case shell according to requirements, replacing the original aluminum bushing, machining the inner ring contact surface of the reinforced aluminum bushing into a final size according to requirements, enabling the fit clearance between the reinforced aluminum bushing and the bearing of the final size to meet the requirements of a drawing, completing the assembly of other parts, forming a complete accessory case, and finally installing the accessory case on the aeroengine.

Description

Maintenance method for reducing out-of-standard fault rate of aluminum element content of lubricating oil of aircraft engine accessory case Technical Field The invention relates to the technical field of aeroengine maintenance, in particular to a maintenance method for reducing the failure rate of exceeding the standard of the content of aluminum element in lubricating oil of an accessory case of an aeroengine. Background The accessory casing is a part for supporting and accommodating a lubricating system, a fuel system and a starting system of the aeroengine and mainly comprises a casing shell, a gear, a bushing, a bearing, a pipeline and the like, wherein lubricating oil is filled in the accessory shell for lubrication, the bushing is usually made of aluminum alloy and is a part positioned between the gear bearing and the casing for reducing abrasion of the casing shell. When the accessory case aluminum liner is assembled, about 1.5mm of allowance needs to be reserved on the matching contact surface of the inner ring of the liner and the bearing, then the axis position of the contact surface of the inner ring of the aluminum liner is determined according to the bearing position, and the contact surface of the inner ring of the aluminum liner is combined and processed to remove the redundant allowance, so that the size of the inner ring of the accessory case aluminum liner meets the drawing requirement. The aluminum element content of the lubricating oil of the accessory case of the aeroengine is higher than the limit value, so that faults are easy to occur, the existing repair method is to decompose the accessory case returned to a factory in advance, take down the worn lining and replace a new lining, however, the inner ring of the existing aluminum lining cannot be provided with a surface hardening layer with enough depth, and therefore, the problem that the aluminum element content of the lubricating oil exceeds the standard due to abrasion still easily occurs after the installation of the new lining. The laser shock strengthening is a novel surface strengthening method, can form higher residual compressive stress on the surface, improves the fatigue strength of the material, improves the surface hardness of the material, generates a deeper hardening layer on the surface, and improves the wear resistance of the material. The method has the potential of being applied to the accessory case aluminum bushing, but the problems that the reinforced part is easy to deform, the size of the reinforced part is changed, the laser shock reinforcement of the complex part is difficult to implement, the part is easy to burn by laser in the reinforcing process and the like are easily caused by the laser shock reinforcement technology. Disclosure of Invention The invention aims to overcome the defects of the prior art, and provides a maintenance method for reducing the failure rate of exceeding the standard of the content of the aluminum element in the lubricating oil of the accessory case of the aeroengine so as to reduce the failure rate of exceeding the standard of the content of the aluminum element in the lubricating oil of the accessory case of the aeroengine. The maintenance method for reducing the failure rate of exceeding the standard of the content of the aluminum element in the lubricating oil of the accessory case of the aeroengine comprises the following steps of: 1) According to the easy-abrasion area of the aluminum bushing of the accessory case to be maintained, determining the corresponding area of the aluminum bushing to be reinforced and processed as a laser impact reinforced area, and setting machining allowance; 2) Determining a deformation control area and machining allowance of the aluminum bushing to be reinforced; 3) Performing laser shock peening pretreatment on the aluminum bushing to be machined in a reinforced mode; 4) And carrying out laser shock peening on a laser shock peening area of the aluminum bushing to be reinforced. The maintenance method for reducing the exceeding failure rate of the content of aluminum element in the lubricating oil of the accessory case of the aeroengine is further better realized, and particularly adopts the following setting mode that the step 1) comprises the following specific steps: 1.1 Taking down an accessory case with exceeding aluminum content of lubricating oil of the aeroengine, decomposing the accessory case, taking down all aluminum bushings, analyzing abrasion marks of the taken down aluminum bushings, and determining an easily-abraded area of the aluminum bushings; 1.2 Setting an easy-abrasion area corresponding to the aluminum bushing to be reinforced and processed as a laser shock strengthening area, and setting machining allowance for the laser shock strengthening area, wherein the machining allowance for the laser shock strengthening area is that if the inner diameter of the aluminum bushing is A at the final delivery time, the inner diameter=