Landing Gear Wheel Retention Assembly for Separated Side and Drag Loads
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Solution Overview
Problem
Conventional wheel retention devices for landing gear fail due to combined side and drag loads during aircraft operation and towing, leading to adverse loading conditions.
Innovation Solution
A wheel retaining assembly with a first and second wheel spacer, a lock ring, and a lock plate that separates side and drag load paths, allowing for in-axle towing without requiring machined threads on the axle, and enabling efficient attachment and removal of auxiliary components like spray deflectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional wheel retention device is used to retain the wheel to the landing gear axle, then the wheel can be retained during aircraft operation and towing, but the device fails due to combined side and drag loads causing adverse loading conditions
Solution Approach 1:
The wheel retention assembly is segmented into distinct functional components: the axle nut handles drag loads only, while the lock ring and lock plate separately manage side loads and positional locking. This segmentation prevents the combined loading that caused conventional single-device failures, allowing each component to be optimized for its specific load type.
2Adaptability or versatility
If machined threads are added to the axle to enable in-axle towing, then in-axle towing becomes possible, but the manufacturing complexity and cost increase
Solution Approach 1:
The towing functionality is extracted from the axle itself and transferred to the lock plate, which includes a tow hole for receiving a tow bar. This eliminates the need to machine threads into the axle, maintaining simple axle manufacturing while enabling in-axle towing capability through the integrated lock plate design.
3Device complexity
If the wheel retention assembly is made as a single integrated component, then the structure is simpler, but maintenance requires complete disassembly of the wheel retention assembly
Solution Approach 1:
The assembly is divided into separable components (axle nut, lock ring, lock plate) that can be independently removed and serviced. The lock ring and lock plate can be detached without removing the wheel itself, enabling maintenance of auxiliary components like spray deflectors while keeping the wheel retained on the axle.
4Device complexity
If the axle nut retains both side and drag loads, then the retention device is simpler, but the axle nut becomes overloaded and fails under repeated adverse loading conditions
Solution Approach 1:
The load-bearing functions are segmented: the axle nut is dedicated to drag loads only, while the lock ring and lock plate handle side loads and mechanical locking. This functional segmentation prevents the axle nut from experiencing combined loading, eliminating the root cause of repeated failures while maintaining overall assembly simplicity.
Data Source
AI summary
A wheel retaining assembly for a landing gear having an axle and an outer wheel bearing, the axle defining an axial direction along an axial centerline, is disclosed. In various embodiments, the wheel retaining assembly includes a first wheel spacer configured to slide over the axle and to abut the outer wheel bearing, the first wheel spacer having an axially outward portion; and a second wheel spacer configured to slide over the axle, the second wheel spacer having an axially inward portion configured to engage the axially outward portion of the first wheel spacer.