Epicyclic Ring Gear Support to Eliminate Spline Wear
Find Innovative SolutionsGenerate Solutions
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 inconsistent balance and deterioration over time, making it difficult to achieve repeatable balance of the turbo fan assembly.
Innovation Solution
The implementation of a tapered bearing on the fan shaft with passages that extend radially and support the ring gear, eliminating the need for a spline ring and providing a direct radial flow path for lubrication, which reduces wear and heat generation while allowing for rotational balance between the turbo fan shaft and ring gear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a splined connection is used between the ring gear and spline ring, then the load can be distributed across multiple contact points, but the connection is still subject to wear and deflection under high loads, leading to inconsistent balance
Solution Approach 1:
The patent removes the spline ring component entirely from the system. Instead of using a splined connection between the ring gear and spline ring, the invention directly couples the ring gear to the output shaft, eliminating the intermediate spline ring that causes wear and balance issues while maintaining load distribution through the gear teeth themselves
Solution Approach 2:
The patent merges the functions of the ring gear and spline ring into a single integrated structure. The ring gear is directly coupled to the output shaft without an intermediate spline ring, combining the gear transmission function with the connection function into one unified component, thereby eliminating the interface that causes wear and deflection
2Ease of operation
If a spline ring is used to connect the ring gear to the turbo fan shaft, then the connection can accommodate radial clearance requirements, but it is difficult to achieve repeatable balance of the turbo fan assembly
Solution Approach 1:
The patent extracts and removes the spline ring from the system, eliminating the component that creates balance variability. The direct coupling of the ring gear to the output shaft removes the intermediate element that prevents repeatable balancing while still accommodating operational requirements
3Power
If a splined connection is used, then the structure can provide torque transmission, but wear under high loads causes balance deterioration over time
Solution Approach 1:
The patent removes the spline ring that is subject to wear, eliminating the source of balance deterioration over time. The direct coupling maintains full torque transmission capability through the gear teeth while removing the intermediate connection that degrades under high loads
Solution Approach 2:
The patent design allows the gear teeth to operate at or near their maximum load capacity continuously, with the direct coupling ensuring that the full torque load is efficiently transmitted without the losses and wear associated with a splined connection, thereby extending the duration of reliable operation
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 solution enhances the durability and balance of the turbo fan assembly by eliminating spline-related issues, reducing wear and heat, and improving the structural rigidity and resistance to overturning moments, thereby maintaining consistent performance over time.
Implementation Method 1
The implementation of a tapered bearing on the fan shaft with passages that extend radially and support the ring gear, eliminating the need for a spline ring and providing a direct radial flow path for lubrication, which reduces wear and heat generation
Implementation Method 2
providing a direct radial flow path for lubrication, which reduces wear and heat generation
Implementation Method 3
A sun gear receives rotational input from a turbine shaft through a compressor shaft. A carrier supports intermediate gears that surround and mesh with the sun gear. A ring gear surrounds and meshes with the intermediate gears.
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, a compressor section, and an epicyclic gear train interconnecting the propulsor shaft and the turbine shaft. The 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. The first and second portions have grooves at the radial interface that form a hole that expels oil through the ring gear.