Rotor Assembly Eccentricity Prediction via Radial Runout and Spring Model
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Solution Overview
Problem
Current methods for calculating the eccentricity of rotor assembly axes in aero-engine rotors are inaccurate due to the rigidity assumption and lack of consideration for elastic deformation, leading to suboptimal assembly and high rates of part out-of-tolerance issues in China's manufacturing environment.
Innovation Solution
A method that calculates eccentricity based on measured radial runout data and considers elastoplastic deformation at spigot joints, using a spring equivalent model to account for uneven assembly interference and deformation, resulting in a more accurate prediction and optimization of assembly phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the fitting circle method based on least square fitting is used to calculate eccentricity, then the calculation procedure is simple and the morphological characteristics of spigot joint surfaces can be grasped as a whole, but the accuracy of predicted eccentricity of axis cannot be guaranteed because the fitting circle cannot fully reflect the amplitude characteristics of the initial morphology
Solution Approach 1:
The patent divides the spigot joint surface morphology into multiple discrete measurement points around the circumference, rather than using a single fitting circle. Each measurement point captures local morphological characteristics, and the eccentricity calculation incorporates individual point deviations, thereby preserving detailed amplitude characteristics while maintaining computational feasibility through segmented analysis.
2Measurement precision
If the actual rotary centerline method is used to predict eccentricity of axis, then the prediction accuracy is high, but it is difficult to adapt to the production and assembly process of aero-engine rotors in China due to restricted manufacturing level and lack of basic aligning and tilt adjusting process for roundness meter
Solution Approach 1:
The patent transforms the measurement parameters from requiring complex roundness meter alignment and tilt adjustment to using simple radial runout measurements at discrete points. By changing the measurement parameters to radial runout values that can be obtained with standard equipment and procedures, the method becomes adaptable to the current Chinese manufacturing environment while maintaining high prediction accuracy through proper mathematical processing of the measured data.
3Ease of manufacture
If the rotor is regarded as a rigid body in concentricity optimization, then the optimization method can be implemented, but the result is slightly different from actual situation because the interference condition of rotor assembly spigot is not considered
Solution Approach 1:
The patent changes the modeling approach from rigid body assumption to elastic deformation consideration by incorporating the interference fit conditions of spigot joints. The mathematical model now includes elastic deformation parameters that account for the actual mechanical behavior during assembly, leading to more accurate concentricity optimization predictions while still being implementable through proper formulation of the optimization problem.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method improves the accuracy of axis eccentricity prediction and optimization, reducing the need for repeated disassembly and assembly, and enhancing the one-time acceptance rate of aero-engine rotor assembly by accounting for actual spigot morphology and deformation.
Implementation Method 1
the interference condition of the rotor assembly spigot is not considered, which is slightly different from the actual situation... in combination with the actual assembly process in a factory, and on the basis of considering the elastic deformation of interference assembly of spigots
Data Source
AI summary
A method for calculating eccentricity of rotor assembly axis based on radial runout measurement comprises matrix characterization of data and calculation of relative runout value at each point, establishment of a spring equivalent model and calculation of contact force, eccentric direction and magnitude; calculation of relative runout value; establishment of a spring equivalent model to analyze the relationship between force and displacement in each phase of a contact process, and then an uneven contact force at each point is obtained; and determination of eccentricity is to determine the magnitude of eccentricity. Based on the measured radial runout data in production practice, this method realizes the prediction of eccentricity of axis before assembly, improves the coaxiality of rotors after assembly, and has important practical guiding significance for axis prediction as well as assembly phase adjustment and optimization in the assembly process of aero-engine rotor pieces.