Planetary Gear Pivot Assembly for Bore Eccentricity Compensation
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Solution Overview
Problem
In turbomachines, epicyclic or planetary gear trains experience disparities in power passing through satellites, leading to mechanical stress overload and premature wear due to relative positioning defects and misalignment of teeth, which complicates assembly and maintenance, increasing costs.
Innovation Solution
An assembly method that orients pivots in planet carrier bores to compensate for eccentricities, allowing each pivot to be compatible with any bore, reducing tangential offset and overload without modifying manufacturing tolerances, and eliminating the need for pairing, thereby simplifying part interchangeability and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pairing is used to reduce satellite overload, then positioning precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent makes all pivots identical and interchangeable, allowing any pivot to be assembled in any bore of the planet carrier. This universal design eliminates the need for pairing operations while maintaining acceptable positioning precision, thereby reducing assembly complexity and manufacturing costs.
Solution Approach 2:
The patent modifies the geometric parameters of the pivots by providing them with non-circular cross-sections (such as square, rectangular, or polygonal shapes) instead of circular sections. This parameter change enables precise positioning in the tangential direction while maintaining interchangeability, resolving the contradiction between positioning precision and assembly complexity.
2Reliability
If pairing is used to reduce satellite overload, then reliability is improved, but ease of manufacture deteriorates
Solution Approach 1:
By making all pivots identical and interchangeable, the patent simplifies manufacturing and assembly operations. Any pivot can be installed in any bore without requiring pairing operations, significantly improving ease of manufacture and assembly while maintaining reliable load distribution through the non-circular cross-section design.
Solution Approach 2:
The non-circular cross-section of the pivots is designed in advance to provide inherent positioning capability. This preliminary design feature ensures correct satellite positioning without requiring complex pairing operations during assembly, thereby improving ease of manufacture while maintaining reliability.
3Manufacturing precision
If pairing is used to reduce satellite overload, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The patent makes all pivots identical and interchangeable, allowing parallel assembly operations to be performed simultaneously. Multiple assembly teams can work on different planet carriers at the same time without requiring complex pairing coordination, significantly improving assembly productivity while maintaining positioning precision through non-circular cross-sections.
Solution Approach 2:
The positioning features are built into the pivot design in advance through non-circular cross-sections. This preliminary action eliminates the need for time-consuming pairing operations during assembly, thereby improving assembly speed and productivity while maintaining manufacturing precision.
4Reliability
If pairing is used to reduce satellite overload, then reliability is improved, but cost increases
Solution Approach 1:
By making all pivots identical and interchangeable, the patent eliminates the need for complex pairing operations and reduces the number of different pivot types that need to be manufactured and inventoried. This universal design reduces production costs while maintaining reliable satellite load distribution through the non-circular cross-section design.
Solution Approach 2:
The non-circular cross-section parameter change provides inherent positioning capability that ensures reliable load distribution. This design modification eliminates the need for expensive pairing operations and complex quality control processes, thereby reducing production costs while maintaining reliability.
Data Source
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AI summary
The invention relates to an assembly method for an epicyclic or planetary gear train of a planet carrier comprising one or more bores, each of the bores being intended to receive a pivot (18), the method comprising the following steps: a) manufacture at least one pivot (18) comprising a real axis (46) distinct from a theoretical axis; b) measure the position of a real axis of each of said one or more bores of the planet carrier; c) for each bore of the planet carrier, mount a pivot (18) in said bore and orient it angularly so that the eccentricity of the pivot (18) compensates at least in part for the eccentricity of said bore.