Spherical-Mounted Roller Bearing for Planet Gear Misalignment
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Solution Overview
Problem
Aircraft propulsion systems face challenges in accommodating misalignments between gears, leading to increased wear and potential failure, particularly in planetary gear systems, due to the complexity and cost of spherical roller bearings and the need for pattern corrections to handle a wide torque band.
Innovation Solution
A spherical mounted cylindrical roller bearing system is introduced, combining a spherical bearing assembly with a cylindrical roller bearing assembly for each planet gear, allowing tilting and rotational movements to accommodate misalignments while reducing design and manufacturing complexities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spherical roller bearings are used to accommodate misalignments, then reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The bearing system is divided into two separate assemblies: an inner bearing assembly with a spherical bearing that handles tilting movements and misalignments, and an outer bearing assembly with cylindrical roller bearings that handle rotational movements and radial loads. This segmentation allows each assembly to be optimized for its specific function, reducing overall system complexity while maintaining reliability.
Solution Approach 2:
The spherical bearing acts as an intermediary element between the planet gear and the carrier post, accommodating misalignments and tilting movements. This intermediary component protects the cylindrical roller bearings from misalignment-related wear and failure, allowing them to operate in their optimal alignment condition.
2Adaptability or versatility
If spherical roller bearings with pattern corrections are used to handle wide torque band, then adaptability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The bearing system is designed to be dynamic rather than rigid, allowing the spherical bearing to tilt and adjust to varying torque conditions. This dynamic capability enables the system to handle a wide torque band without requiring precise pattern corrections, as the spherical bearing naturally adapts to different load conditions through its tilting motion.
Solution Approach 2:
The spherical bearing changes its operational parameters (tilt angle, contact point) in response to varying torque conditions. This parameter change allows the bearing system to adapt to a wide torque band without requiring complex pattern corrections, effectively decoupling adaptability from manufacturing precision requirements.
3Reliability
If a stiff and heavy carrier is used to maintain radial loading, then reliability is improved, but weight increases
Solution Approach 1:
The spherical bearing provides a flexible mounting solution that maintains radial loading on the cylindrical roller bearings without requiring a stiff and heavy carrier. The spherical bearing's ability to tilt and adjust allows it to maintain proper loading conditions while being lighter than a rigid carrier structure would be.
Solution Approach 2:
The function of maintaining radial loading is extracted from the carrier structure and transferred to the bearing system itself. The spherical bearing assumes the role of maintaining proper loading conditions, allowing the carrier to be lighter and less stiff while still ensuring reliable operation of the cylindrical roller bearings.
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 effectively maintains radial loading without the need for a stiff and heavy carrier, reducing manufacturing costs and design complexities associated with spherical roller bearings and pattern corrections, while supporting both tilting and rotational movements.
Implementation Method 1
an inner bearing assembly comprising a spherical bearing and an outer race
Implementation Method 2
an outer bearing assembly comprising a plurality of cylindrical roller bearings, an inner race, and an outer race
Data Source
AI summary
A bearing system is provided in one example embodiment and may include an inner bearing assembly comprising a spherical bearing and an outer race; an outer bearing assembly comprising a plurality of cylindrical roller bearings, an inner race, and an outer race; and a race element comprising an inner surface and an outer surface, wherein the outer surface of the race element is the inner race for the outer bearing assembly and the inner surface of the race element is associated with the outer race for the inner bearing assembly. The inner bearing assembly allows tilting movements of the bearing system and the outer bearing assembly allows rotational movements and supports, at least in part, radial loads for the bearing system.