Planetary Gear Train Assembly for Pivot-Bore Axis Alignment
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Solution Overview
Problem
Current epicyclic and planetary gear trains in turbine engines face mechanical stress overload due to relative positioning errors of planet gears, leading to premature wear and increased maintenance costs, with existing solutions complicating part inventory management and assembly processes.
Innovation Solution
A process for assembling epicyclic or planetary gear trains involves measuring and orienting pivot and carrier bore axes to minimize eccentricity, using angular sectors and form-fitting coupling means to ensure correct alignment without requiring part pairing, allowing for interchangeable parts and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pairing operations are used to reduce planet gear positioning errors, then manufacturing precision is improved, but device complexity and ease of manufacture deteriorate due to complex assembly tasks and part inventory management
Solution Approach 1:
The patent changes the approach from modifying parts (pairing) to modifying the assembly process parameters. By measuring real axes positions and calculating optimal angular orientations, the method achieves precise positioning through parameter optimization rather than physical part modification or complex pairing operations.
Solution Approach 2:
The patent performs preliminary measurement of real axes positions and preliminary calculation of optimal angular orientations before assembly. This preliminary action allows the assembly process to simply implement pre-determined orientations, avoiding complex real-time pairing operations during assembly.
2Manufacturing precision
If pairing operations are used to reduce planet gear positioning errors, then manufacturing precision is improved, but productivity deteriorates due to constrained assembly operations
Solution Approach 1:
The patent performs all complex calculations and determinations of optimal orientations before assembly. During actual assembly, workers simply need to orient components according to pre-calculated values, significantly reducing assembly time and improving productivity while maintaining high precision.
Solution Approach 2:
The patent replaces complex mechanical pairing operations with a measurement-calculation-orientation process. Instead of physically matching surfaces or features through trial and error, the method uses measured data and calculated orientations to directly achieve precise positioning, streamlining the assembly process.
3Manufacturing precision
If manufacturing tolerances are tightened to reduce positioning errors, then manufacturing precision is improved, but ease of manufacture deteriorates due to increased manufacturing costs
Solution Approach 1:
The patent changes from controlling manufacturing parameters (tolerances) to controlling assembly parameters (orientations). By measuring actual positions and calculating optimal assembly orientations, the method achieves high precision without requiring expensive tight manufacturing tolerances, thereby reducing manufacturing costs.
Solution Approach 2:
The patent uses feedback from measurement of real axes positions to determine optimal assembly orientations. This feedback mechanism allows the assembly process to compensate for manufacturing variations, achieving high precision without needing extremely tight manufacturing tolerances, thus reducing manufacturing costs.
Data Source
AI summary
The invention concerns a process for the assembly of an epicyclic or planetary gear train from at least one pivot (18) and a planet gear carrier (20) comprising one or more bores, each of said bores being intended to receive a pivot (18), the process comprising the following steps:a) measuring the position of a real axis of each of said at least one pivot (18) and of said one or more bores of carrier (20);b) dividing each of said pivots (18) into n angular sectors i1 . . . iq . . . in extending about the theoretical axis of said pivot and dividing each of said holes of the carrier (20) into k angular sectors j1 . . . jl . . . jk extending about the theoretical axis of said bore;c) for each pivot (18), defining a vector {right arrow over (V)} oriented from the theoretical axis to the real axis, and identifying the angular sector iq including vector −{right arrow over (V)};d) for each bore, defining a vector {right arrow over (U)} oriented from the theoretical axis to the real axis, and identifying the angular sector jl including vector {right arrow over (U)};e) for each bore of the carrier (20), mounting a pivot in such a way that for each mounting, the identified angular sectors jl and iq are superimposed.