Aircraft Landing Gear Bogie Pivot Axis Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing aircraft landing gear systems with multi-axle configurations face issues with brake rod anchor points experiencing high bending moments and reducing ground clearance or restricting other features, as they induce pitching moments during braking and require additional space.
Innovation Solution
A coupling assembly that defines a remote bogie beam pivot axis spaced from the landing gear assembly, allowing the bogie pivot to be positioned level with the ground, eliminating the need for brake rods and enabling local mechanical fixation of brake assemblies, thereby minimizing pitching moments and optimizing space usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brake rods are used to couple brake assemblies to the main strut, then braking function is achieved, but large bending moments are experienced at anchor points and pitching moments are induced on the bogie beam
Solution Approach 1:
The invention extracts the brake rod anchor point from the main strut and relocates it to the bogie beam itself. The brake assemblies are now locally fixed to the bogie beam at or near the wheel assembly locations, eliminating the need for long brake rods extending to the main strut. This removes the anchor points from the high-stress environment of the main strut while maintaining effective braking.
Solution Approach 2:
The bogie beam serves as an intermediary structure that directly couples the brake assemblies to the wheel assemblies. Instead of using brake rods as intermediaries between the main strut and brake assemblies, the bogie beam itself becomes the coupling structure, with brake assemblies locally fixed to it. This intermediary approach eliminates the need for separate brake rods and their anchor points.
2Reliability
If brake rods are placed below the bogie beam, then braking function is achieved, but ground clearance is reduced
Solution Approach 1:
The brake assemblies are locally fixed to the bogie beam at specific locations near the wheel assemblies, rather than using centralized brake rods. This local quality approach allows the brake function to be performed at the exact location where it is needed, eliminating the need for brake rods that would extend below the bogie beam and reduce ground clearance.
3Length of moving object
If brake rods are placed above the bogie beam, then ground clearance is maintained, but other features such as torque links or pitch trimmer are restricted
Solution Approach 1:
The brake assemblies are positioned in the lateral dimension at or near the wheel assemblies, rather than being positioned above or below the bogie beam in the vertical dimension. This dimensional change allows the brake function to be performed without occupying vertical space that would conflict with other features like torque links or pitch trimmers, while maintaining ground clearance.
4Reliability
If local mechanical fixing is used to connect brake assemblies to the strut, then braking function is achieved, but pitching moments are induced on the bogie beam
Solution Approach 1:
The brake assemblies are positioned at or near the bogie beam pivot axis, creating an equipotential condition where the braking force acts through or near the pivot point. This minimizes the moment arm and reduces pitching moments on the bogie beam, while still achieving effective braking through local mechanical fixing.
Data Source
AI summary
An aircraft landing gear assembly having a main strut and a bogie beam pivotally coupled to the main strut via a coupling assembly. The coupling assembly is arranged to define a bogie beam pivot axis which is spaced from the landing gear assembly. The coupling assembly includes an arcuate handle portion defined by a first one of the bogie beam and the main strut, and an arcuate passage defined by the other one of the bogie beam and main strut. The arcuate handle portion is slidably housed within the arcuate passage, and the arcuate handle portion and the arcuate passage each define a respective centre point, the respective centre points being coaxial to define the bogie beam pivot axis.