Spline Assembly With Melt-Away Spherical Alignment Head
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Solution Overview
Problem
The existing spline assembly systems in aircraft, particularly in rotary aircraft like helicopters, face challenges in aligning the spline shaft with the spline receiver due to the distance between the hydraulic pump and the gear, making initial assembly and servicing difficult, and often require special tools, which can lead to damage and increased weight.
Innovation Solution
A spline assembly with a spherical alignment terminal on the spline shaft that mates with a slightly flared terminal on the spline receiver, allowing for easier alignment and preventing damage, and optionally using a disposable hydrocarbon ball terminal that mixes with lubricant fluid and is removed during oil changes to reduce weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional spline shaft is used without alignment features, then the structure remains simple and lightweight, but alignment with the spline receiver becomes difficult and requires special tools
Solution Approach 1:
A spherical alignment head is introduced as an intermediary element between the spline shaft and the spline receiver. This spherical head fits into a corresponding spherical recess in the receiver, providing a self-aligning mechanism that guides the shaft into proper alignment during assembly, eliminating the need for special alignment tools
Solution Approach 2:
The alignment feature utilizes a spherical geometry at the end of the spline shaft that mates with a spherical recess in the receiver. This curved surface interaction provides automatic alignment capability, allowing the shaft to be easily guided into the correct position without requiring precise manual alignment or specialized tooling
2Manufacturing precision
If special alignment tools are used to align the spline shaft, then alignment precision improves, but the risk of damage increases and weight increases
Solution Approach 1:
The spherical alignment head acts as a protective intermediary that distributes alignment forces evenly across the mating surfaces. This prevents concentration of stress at specific points, thereby reducing the risk of damaging the spline teeth or other critical components during the alignment process
Solution Approach 2:
The spherical geometry provides a cushioning effect during alignment, allowing for gradual and controlled engagement between the shaft and receiver. This prevents sudden impacts or misalignment forces that could cause damage, as the curved surfaces guide the components into proper alignment smoothly
3Ease of operation
If a permanent alignment head is used, then alignment capability is maintained, but unnecessary weight is added to the assembly
Solution Approach 1:
The alignment head is designed as a disposable component that is removed after assembly. This allows the system to have alignment capability during assembly operations while avoiding the permanent weight penalty of an always-present alignment feature. The head is discarded after serving its alignment purpose, leaving only the essential spline components
Solution Approach 2:
The alignment head is extracted or removed from the assembly after it has served its alignment function. This separates the alignment function (needed only during assembly) from the operational components, allowing the final assembled system to be lighter while still having had the alignment capability when needed
Data Source
AI summary
A spline assembly, including a spline shaft having a first end and a second end, wherein the first end is splined to engage a spline receiver of a primary drive system and includes a substantially spherical alignment head, wherein the spherical alignment head comprises an expendable hydrocarbon material that is caused to melt by operation of the primary drive system over time.