Compressor Hub Merging LPT Shaft for Geared Fan Drive
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Solution Overview
Problem
The complexity of connecting the low pressure turbine (LPT) to the fan drive gear system in two-spool turbofan engines increases due to the numerous tightly arranged components, complicating independent control of the LPT/fan speed ratio, which is essential for efficiency, noise reduction, and performance improvement.
Innovation Solution
A compressor hub design featuring a cylindrical sleeve portion, a frustoconical cone portion, and a mounting flange portion, with inner and outer splines, allows for a single-piece construction that increases stiffness while minimizing weight and simplifies the connection between the LPT and fan drive gear system, enabling independent speed control and improved torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a geared fan drive system is used to provide independent control of LPT/fan speed ratio, then engine efficiency and performance are improved, but device complexity increases due to numerous tightly arranged components
Solution Approach 1:
The patent combines the LPT shaft and compressor hub into a single integrated assembly, eliminating the need for separate connection components. The compressor hub is directly coupled to the LPT shaft, merging functions that were previously handled by multiple discrete parts, thereby reducing device complexity while maintaining the geared fan drive system's speed control capabilities
Solution Approach 2:
The compressor hub serves multiple functions: it supports the LPT shaft, provides mounting for compressor blades, and acts as a structural element for the engine assembly. This multi-functional design reduces the number of dedicated components needed, simplifying the overall connection between the LPT and fan drive gear system
2Ease of manufacture
If multiple components are used to connect LPT to fan drive gear system, then flexibility in assembly is improved, but manufacturing precision requirements increase due to tight arrangement
Solution Approach 1:
By integrating the LPT shaft and compressor hub into one piece, the patent eliminates the need for high-precision alignment between multiple separate components. The single-piece construction inherently satisfies precision requirements while maintaining assembly flexibility through design features like splines and mounting interfaces
3Strength
If a single-piece compressor hub design is used, then structural integrity is improved, but manufacturing complexity increases
Solution Approach 1:
While the compressor hub itself is a single-piece component, the patent uses segmented design features within it, such as splines on the LPT shaft and mounting flanges for rotor disks. These segmented features are integrated into the single-piece hub, allowing complex functions to be achieved through design rather than assembly, balancing structural integrity with manufacturability
Data Source
AI summary
A compressor hub includes a sleeve portion, a cone portion, and a mounting flange portion. The sleeve portion is cylindrical about a sleeve axis. The frustoconical cone portion is attached to the sleeve portion and diverges radially outward. In addition, the cone portion includes an inner cone portion with an inner generatrix and an outer cone portion with an outer generatrix that is colinear with the inner generatrix. The mounting flange portion is attached to the outer cone for attaching a rotor disk to the compressor hub.