Modular PDU Wheel Assembly with Segmented Disc Stack
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Solution Overview
Problem
Conventional PDU tires in aircraft cargo handling systems require frequent replacement due to chipping, leading to increased maintenance costs and reduced traction effectiveness.
Innovation Solution
A modular wheel assembly featuring a splined hub with a disc stack comprising rings and annular segments made of different materials, where the terminal discs are made of a chip-resistant material and the distal discs are made of a traction-providing material, with a holding screw and stopper mechanism to secure the disc stack and prevent slippage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PDU tires are used with friction material molded onto a rigid hub, then adequate traction is provided, but the tires require frequent replacement due to chipping
Solution Approach 1:
The wheel assembly is divided into separable components: a rigid hub and multiple disc elements that can be independently replaced. The friction material is applied only to specific disc elements that contact the cargo, allowing selective replacement of worn friction surfaces without replacing the entire wheel assembly.
Solution Approach 2:
Different materials are used for different parts of the wheel assembly. The rigid hub provides structural strength, while the disc elements provide friction for traction. The friction material is applied locally only to the portions of discs that contact cargo, optimizing both durability and traction where needed.
2Reliability
If the entire wheel assembly is replaced when tires wear out, then traction effectiveness is restored, but maintenance costs increase
Solution Approach 1:
The wheel assembly is segmented into a permanent hub and replaceable disc elements with friction surfaces. When friction material wears or chips, only the affected disc elements need replacement, not the entire wheel assembly, significantly reducing maintenance costs.
Solution Approach 2:
The rigid hub and non-worn components are retained and reused. Only the worn friction surfaces on disc elements are replaced, allowing recovery and continued use of durable components while replacing only the consumable friction materials.
3Reliability
If a modular disc stack design is used with different materials for terminal and distal discs, then wear resistance and traction are optimized, but device complexity increases
Solution Approach 1:
Different material properties are assigned to different positions in the disc stack: terminal discs use chip-resistant material for durability, while distal discs use high-friction material for traction. This localized optimization improves overall performance without requiring complete redesign of the entire assembly.
Solution Approach 2:
The wheel assembly uses composite construction with different materials for different functional requirements. Terminal discs employ wear-resistant materials, while distal discs use traction-optimized materials, creating a composite structure that leverages the strengths of each material where most needed.
Data Source
AI summary
A modular wheel assembly for a power drive unit (PDU) may comprise a hub and a disc stack coupled to the hub. The hub may be a splined hub defining a plurality of spline recesses. The disc stack may comprise a plurality of discs. Each disc of the plurality of discs may comprise a ring having a plurality of splines that are complementary to the spline recesses, and that are configured to interlock with the spline recesses. Each disc may further comprise an annular segment made of one of a first material and second material. The annular segment may be a tire. In the event of damage or wear, each disc in the plurality of discs may be removed and repaired or replaced.