Flexpin Epicyclic Gear System Alignment and Maintenance
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Solution Overview
Problem
Epicyclic gear systems with straddle-type carriers experience skewing of pins due to torque-induced distortion, leading to misalignment between planet pinions and sun/ring gears, necessitating costly replacement of entire transmissions when components become damaged.
Innovation Solution
The use of flexpins with a double cantilever design, where each flexpin is anchored at one end and has a sleeve extending radially to support planet pinions, maintains alignment and allows for modular replacement of components by employing a self-locking taper mechanism for secure attachment and easy detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If straddle-type carrier with rigid pins is used, then structural stability is improved, but pin skewing and gear mesh alignment deteriorate under torque load
Solution Approach 1:
The patent changes the physical state of the pin from rigid to flexible by introducing a bendable portion with reduced cross-sectional area. This parameter change allows the pin to deform elastically under torque, compensating for carrier distortion and maintaining gear mesh alignment while preserving overall structural stability.
Solution Approach 2:
The patent transforms the static rigid pin into a dynamic flexible pin that can adapt its shape in response to applied loads. The flexible pin bends to accommodate carrier windup distortion, dynamically maintaining proper alignment between planet pinions and sun/ring gears under varying torque conditions.
2Reliability
If entire transmission is replaced when components are damaged, then system reliability is improved, but maintenance cost and complexity increase
Solution Approach 1:
The patent segments the transmission system into modular components: carrier, flexible pins, planet pinions, and gear sets. This segmentation allows individual components to be replaced independently rather than replacing the entire transmission, reducing maintenance cost and complexity while maintaining system reliability through targeted repairs.
Solution Approach 2:
The patent enables selective replacement of worn or damaged components (flexible pins, planet pinions) while retaining functional components (carrier, gear sets). This approach recovers valuable components and reduces waste, lowering maintenance costs while ensuring reliability by replacing only the necessary parts.
3Manufacturing precision
If flexpin with double cantilever design is used, then gear mesh alignment is improved, but device complexity increases
Solution Approach 1:
The flexible pin is segmented into distinct functional portions: a first portion with larger cross-sectional area for structural support, a bendable portion with reduced cross-sectional area for alignment compensation, and a second portion for connection. This segmentation achieves precise gear mesh alignment while keeping each segment's design relatively simple.
Solution Approach 2:
The patent uses parameter changes in the pin's cross-sectional area to create the flexible double-cantilever structure. By reducing the cross-sectional area in the bendable portion, the pin gains the necessary flexibility for alignment compensation without requiring complex mechanical structures or additional components.
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 design mitigates skewing, ensures proper mesh alignment, and facilitates the modular replacement of damaged components, reducing maintenance costs and complexity in wind turbine transmissions.
Implementation Method 1
the flexpin bends in one direction circumferentially relative the main axis of the system and at the opposite end bends circumferentially in the other direction, so that the sleeve remains parallel to the axis
Data Source
AI summary
A flexpin assembly (B) for an epicyclic gear system (A) includes a flexpin (20) that at one end is cantilevered from a carrier end wall (12) and a sleeve (22) that surrounds the flexpin and is cantilevered from the flexpin at the other end of the flexpin. In addition, the assembly has an antifriction bearing (24) for supporting a planet pinion (6) around the sleeve. The flexpin has a base (30) that is configured to be anchored to a carrier wall, a head (32) to which the sleeve is attached, and a shank (34) located between the base and head. The sleeve has a mounting segment (78) that is connected to the head of the flexpin without a weld. Both may have tapered surfaces secured in contact by a plate (66) clamped against the mounting portion with screws (68) that thread into the head, thus enabling the sleeve to be detached from the pin. The head may have a cylindrical surface (72) over which the mounting segment of the sleeve fits with an interference fit exists. The bearing may have rolling elements (106, 108) that surround raceways (86, 88) on the sleeve and a rib ring (94) that confines the rolling elements axially, but can be detached. The flexpin assembly is easily disassembled to facilitate servicing of the gear system.