Two-Piece Ring Gear Mounting to Reduce Wear and Oil Windage
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Solution Overview
Problem
The splined connection between the ring gear and spline ring in epicyclic gear trains of gas turbine engines experiences wear and deflection under high loads, leading to imbalance and durability issues due to radial clearance, which complicates repeatable balance and can deteriorate over time.
Innovation Solution
A two-piece ring gear construction with angled teeth and a trough between portions, secured by bolts, eliminates the need for a spline ring, incorporating knife edge seals and an oil baffle to inhibit axial oil flow and reduce windage, while allowing radial balancing of the turbo fan shaft and ring gear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a splined connection is used between the ring gear and spline ring, then the connection can accommodate radial clearance and allow assembly, but the connection experiences wear and deflection under high loads leading to imbalance
Solution Approach 1:
The invention extracts and eliminates the spline ring component from the system. By directly connecting the ring gear to the turbo fan shaft without an intermediate spline ring, the patent removes the source of wear and deflection while maintaining assembly capability through direct bolting of the ring gear to the shaft.
2Ease of manufacture
If radial clearance is provided in the spline connection, then assembly is facilitated, but repeatable balance becomes difficult to achieve and deteriorates over time
Solution Approach 1:
The invention merges the ring gear and turbo fan shaft into a directly connected assembly, eliminating the intermediate spline connection. This integration allows the ring gear to be directly bolted to the shaft, achieving both easy assembly and precise, repeatable balance by removing the clearance-introducing intermediate component.
3Ease of operation
If a spline ring is used to connect the ring gear and turbo fan shaft, then the connection can be assembled with radial clearance, but windage and heat generation increase
Solution Approach 1:
The invention extracts and removes the spline ring from the power transmission path. By directly connecting the ring gear to the turbo fan shaft, the patent eliminates the additional surface area and clearance that cause windage losses and heat generation, thereby reducing energy loss while maintaining assembly capability.
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 configuration enhances structural rigidity, reduces heat generation, and improves balance by eliminating radial movement and axial oil flow, resulting in improved durability and reduced wear, thereby stabilizing the turbo fan assembly.
Implementation Method 1
knife edge seals and an oil baffle to inhibit axial oil flow
Implementation Method 2
an oil baffle to inhibit axial oil flow
Data Source
AI summary
A gas turbine engine according to an example of the present disclosure includes, among other things, a propulsor section including a propulsor supported on a propulsor shaft, a turbine section including a turbine shaft, and an epicyclic gear train interconnecting the propulsor shaft and the turbine shaft. The epicyclic gear train includes a sun gear coupled to the turbine shaft, intermediary gears arranged circumferentially about and meshing with the sun gear, a carrier supporting the intermediary gears, and a ring gear including first and second portions each having an inner periphery with teeth intermeshing with the intermediate gears. The first and second portions have axially opposed faces abutting one another at a radial interface and respective flanges extending along the radial interface radially outward from the teeth. The first and second portions define a trough axially between and separating the teeth of the first portion from the teeth of the second portion. The first and second portions include facing recesses that form an internal annular cavity along the radial interface.