Shallow talk about RB211 fan casing to prevent grind belt repair

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  • source:KAIHER CNC Machining
RB211 engine is a civil aviation that Luo Gong of British collect · manages development is developed large 3 rotor engine. This engine reachs dependability with its good performance by domestic and international much home airline is chosen (see a picture 1) . Ameco has the aviation of ability of this engine overhaul exclusively to maintain an industry as home, after having capacity of this engine overhaul from 1993, repairing deepness and range to go up to send driving to take ceaselessly, carry the development of oneself ability, obtained a series of achievement. Repair plan engine of analytic   RB211 is prevented grind of the belt repairing repair manual to undertake according to what the company offers Luo Luo. Repaired main purpose is the apex clearance that restores fan lamina. The 75% above of RB211 engine thrust arise by fan lamina, through controlling the bulk of apex clearance, can achieve raise engine thrust, improve the purpose of engine function thereby. Prevent grind of the belt repair the function to engine to having very big effect, accordingly, former production manufacturer is ground to preventing of the belt repair normative requirement particularly strict also. Accordingly, how to control the apex clearance of fan lamina strictly, make its satisfy the size limit that manual place asks, become us to need settlement main problem. As we have learned, when department of collect · Luo Gong is carrying out this to repair the task, used an appropriative to machine a tool, this tool is covered go up in engine main shaft, it is the centre of a circle with engine main shaft, in overall undertake circumgyrate is machined below condition. But this tool is not for sale, and the price is very high; Additional, repair cycle to decrease, we are undertaking fan casing is prevented grind of the belt when repairing, engine has been decomposed, fan casing is in sheet condition, accordingly, we must be used other repair a method to solve this problem. Repaired concrete step   (1) RB211 engine is in when taking a plant, did not decompose in engine before, measure the apex interval of fan lamina according to the requirement of manual, dimension asks to be: Leading edge 0.

508 ~ 2.

54mm; Tailing edge 1.

524 ~ 3.

00mm. After gap measure exceeds this measure, must grind to preventing according to manual belt undertake repairing, in order to restore apex clearance (see a picture 2) . (2) the specific operation method that manual provides is: (A) OMAT874 of Tu Fula glue and solidify; (B) the method that adopts machine treatment or manual burnish restores to prevent wear the size of the belt. (3) ends in engine installation, be in in the ala, below the condition that gear case installs, according to manual the requirement measures apex interval, make apex gap measure is in measure (inside the dimension clearance limits that 1) place asks. The problem   that Nextpage   repairs the place in the process to want to solve (1) this repairman makes perforative and whole engine repair a process from beginning to end. Begin into the factory from engine, to engine installation is finished, the installation before test-drive arrives on hanger, a time that growing so paragraph (engine repairs cycle to control) for 75 days commonly, how have the job effectively reasonably coordinate and be being arranged is the problem that the 1st need solves. (2) of clearance of the apex when engine takes a plant measuring is by the machinery of general assembly workshop section member finish; The measurement in repairing a process repairs personnel to finish by what repair workshop section; Be being measured finally of the stage in the car is by test-drive machinery member those who finish. Because be between fan lamina and fan hub,have space (see a picture 3) , accordingly, the gimmick weight of different operation personnel is different will cause measure a result to differ, make data fuzzy thereby, this is the 2nd issue that we need to solve. (3) when apex interval is being measured into factory and car stage in engine, engine has been installed finish, 2 element that make gap -- fan lamina and prevent grind belt had reached the designated position, such ability measure apex interval. But sheet is in in fan casing when condition, fan lamina is nonexistent, the gap measure requirement that the ply dimension of the coating after how control burnish makes its satisfy final engine to fall in alary condition is the 3rd issue that we want to solve (see a picture 2 with the graph 4) . (4) of apex clearance check and accept finally measuring is in engine whole installation ends, gear case already was installed, engine undertakes below alar condition, and the apex clearance when taking a plant measures engine is be in in engine 3, when supporting the position at 9 o'clock, get, of fan casing repairing is in fan casing is in sheet undertake below condition. Because fulcrum is different, the deflection of casing of fan of disadvantageous position of these 3 kinds of position is not identical also, want a basis 3, propped up next data that measure earning to arrive at 9 o'clock, in sheet undertake repairing below condition, the apex gap measure that satisfies engine to fall in alary condition in car stage thereby asks, it is the 4th issue that we need to solve.   of means of settlement (1) to before 2 problems, we were adopted by branch of a function, the same individual that is branch of a function even will finish engine to be in into sheet of factory, casing repair, of measure of the gap before test-drive measure. Adopt this method, utmost ground assured the accuracy of data, in the meantime, the application of this kind of method also can make particular staff member can right casing of each engine fan is prevented grind of the belt repair a process to have a complete knowledge. Handlers passes the measurement of pair of data that take a plant to analyse, can adjust in repaired process the daub ply of glue, the measure that ultimate car stage leaves in alary condition measures repass, can master the influence that is out of shape as a result of casing to clearance place is caused further, control the ply of the glue of different position conciously then, inside the dimension range that offers in manual place, to different position, find out the dimension space with a less scope, pass what repair experience certainly to accumulate, adopt the method of recurrence finally, find out a the most reasonable casing sheet the dimension clearance below condition, pass the dimension gap with these different narrow position, the complete control of the clearance of fan lamina apex that obtains final engine to fall in alary condition thereby. (2) be in to fan casing odd the control of a ply of the coating below condition, through fumbling, research, we abstained tool of a simulation (see a picture 5 ~ 7) come the condition of imitate fan lamina, the method controlled the maths of use analogy successfully to prevent grind the opposite thickness that takes coat. Nextpage     (A) was not decomposed into the factory in engine, and for 3, when was being propped up at 9 o'clock, use appropriative measures tool, according to the measurement technique that manual place offers, part leading edge of winkle fan lamina is the longest with tailing edge the longest lamina. The lamina of reuse place winkle, apex of leading tailing edge is inward 12.

The position of 7mm, be in respectively 8 positions that the graph shows 8 times measure fan blade and prevent obliterate the gap between the belt, clearance of apex of the engine when getting taking a plant measures a watch (see a table 1) . Nextpage     (B) is in fan casing is odd below condition, clearance of apex of the engine when taking a plant according to what measure A earning arrives measures a watch, through abstaining tool (see a picture 9) , control the opposite ply of coating. Particular operation measure is: In 8 positions, put apart is wide measure the place for what 10mm controls, these 8 positions not gelatinize. Besides the size that other position measures gotten clearance to measure a watch according to the engine when taking a plant, daub is certain the blue glue of ply, after daub ply must satisfy burnish, can restore to prevent worry the demand that takes measure. After La Jiaogu is changed and preliminary burnish is finished, of lamina of use imitate fan abstain tool (lower the around edge that 2 slippery needles represent fan lamina respectively measures the place, 10) seeing a picture slips through adjusting 2 needle, make its reach the engine when taking a plant respectively in 8 afore-mentioned positions the longest lamina is in the gap measure of the around predestined relationship of these 8 positions, rotational simulation tool measures lever, measure these 8 places of area of blue glue of around besmear Fu prevent grind the gap measure between belt and slippery needle, inside the dimension clearance that makes sure this dimension sets in manual (leading edge: 0.

508 ~ 2.

54mm, tailing edge: 1.

524 ~ 3.

00mm) . Be in with these 8 size control every position both sides the area of each 1/16, obtain control thereby whole casing is prevented wear the size of the belt. This kind of method is differentiate casing for 8 area, the measure of the circular arc area that will control 1/8 is used in every area. Via test and verify, this method is completely feasible. (3) through nearly one year many many 20 of engine try long, be in to fan casing into the factory 3.

Propped up at 9 o'clock, odd a condition, in alary condition be out of shape, and in into the factory 3.

Was propped up at 9 o'clock and the change of clearance of fan lamina apex issues in alary condition, we had mastered much data, pass the analysis of these pair of data, the qualitative analysis conclusion that the deflection that gets fan casing fall in these 3 kinds of different position affects to clearance. It is with the tailing edge data of 3 engine now exemple (see a table 1) , show the change of apex clearance. From the watch 1 in data we can induce piece: Engine takes a plant 3.

Propped up at 9 o'clock with gear case installation, engine is in compare in alary condition photograph, decrescent of on half clearance, below half clearance greatens. Why can you have such change? Is this kind of change ground to preventing of the belt specific repair what effect is there? This is the problem that we need to know and should solve. Of the deflection that if because the differ and causes fan casing of strong point is in,consider only,3 kinds of condition issue different, criterion if pursue,its are out of shape 10 are shown. Condition 1 install for gear case, 3, supported position at 9 o'clock, as a result of the gravitational action of gear case, below fan casing half are down overhang; Condition 2 for sheet, gear case was not installed, 3, supported position at 9 o'clock, can think fan casing is free condition; Condition 3 install for gear case, engine at 12 o'clock condole orders suspension. Differ in fulcrum, gear case installs the premise with different position to fall, as a result of,fan axis still gets hind the different and generation is different pitch angle of fulcrum, cause casing of fan of zephyr of fan lamina apex to prevent thereby grind between the belt the change of clearance. Pass many measurement, we reached express the clearance change trend of 1. According to this trend graph, we are prevented in executive fan casing grind belt when repairing, general according to the following 2 principles will carry out: (A) is ground to entering factory examination to prevent take apex gap measure not the place of out of tolerance, according to the program that manual place asks, tu Fuyi layer is thin thin adornment sex blue glue. (B) grinds the place that takes out of tolerance of apex gap measure to entering factory examination to prevent, undertake repairing according to manual while, farther to the ply of coating still partition undertakes fan casing is divided into 4 area controlling keeping watch namely, specific size control sees a table 2. The last word passes the execution of above measure, RB211 fan casing is prevented ground the repair difficult problem of the belt to get settlement eventually. Undertake repairing according to this method to nearly ten engine through us, proving this method is reasonable, lawful, feasible. CNC Milling