Aircraft Turbomachine Reduction Gear With Split Ring Gear Assembly
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Solution Overview
Problem
The existing mechanical reduction gears for turbomachines, particularly in dual-flow configurations, face challenges due to their large radial dimensions and complex fastening methods, which impact the overall size and efficiency of the gear assembly.
Innovation Solution
The proposed solution involves a mechanical reduction gear design where the ring gear is rotationally fixed to two separate shafts using an annular covering part with independent fastening means, such as flanges and splines, eliminating the need for large radial webs and allowing for a more compact and rigid assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the ring gear is formed by two coaxial half-ring gears connected by frustoconical webs, then the structural integrity is maintained, but the radial dimensions of the assembly increase significantly
Solution Approach 1:
The ring gear is divided into two independent coaxial half-ring gears that are spaced apart by an annular space. Each half-ring gear is independently fastened to the covering part and shaft using flanges and splines, eliminating the need for connecting webs and reducing radial dimensions while maintaining structural integrity through independent support.
2Stability of the object's composition
If the half-ring gears are fastened using traditional web connections, then the assembly is structurally sound, but the fastening method becomes complex and increases radial space requirements
Solution Approach 1:
An annular covering part is introduced as an intermediary component between the half-ring gears and the shafts. This covering part provides a simplified fastening interface using flanges and splines, reducing assembly complexity while ensuring stable connection. The covering part independently fastens each half-ring gear to the respective shaft, eliminating complex web connections.
3Device complexity
If the ring gear uses a single shaft connection, then the assembly is simpler, but the torque transmission capability and rigidity are reduced
Solution Approach 1:
The single shaft connection is segmented into two separate shaft connections, with each half-ring gear independently fastened to its own shaft. This segmentation allows torque to be distributed across two independent transmission paths, doubling the torque transmission capability while maintaining assembly simplicity through standardized fastening interfaces.
4Length of stationary object
If the half-ring gears are positioned close together, then the radial space is minimized, but the lubrication and heat dissipation are compromised
Solution Approach 1:
Instead of positioning the half-ring gears as close as possible, an annular space is intentionally maintained between them. This excessive spacing prioritizes lubrication flow and heat dissipation over minimal radial space, allowing proper lubricant circulation and thermal management while still achieving compact overall dimensions through the covering part design.
Data Source
AI summary
A mechanical reduction gear is suitable for a turbomachine and, in particular, a turbomachine of an aircraft. The reduction gear includes a sun gear, a ring gear formed by two half-ring gears, planet gears arranged between the sun gear and the ring gear, and at least one shaft rotationally fixed to the ring gear. The reduction gear further includes an annular covering part that extends around the ring gear and is independently fixed by flanges and/or splines to each of the half-ring gears.