Independent Bogie Beam Landing Gear for Tyre Deflation Load Equalization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional aircraft landing gear systems are inefficient in distributing load evenly across multiple axles, leading to increased weight and maintenance requirements due to the inability to pivot and adjust for differences in rolling radius caused by deflated tires, resulting in excessive stress on components.
Innovation Solution
A dual bicycle arrangement of parallel bogie beams that can pivot independently to maintain equal wheel loading, with flexible bearing regions allowing wheel rims to contact the ground in case of tire deflation, and segregation of braking systems for improved safety and reduced maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional landing gear with fixed bogie beams is used, then structural simplicity is maintained, but weight increases due to over-engineering for worst-case load scenarios
Solution Approach 1:
The landing gear is divided into two independent bogie beams instead of one rigid structure. Each bogie beam can pivot independently about its mounting axis, allowing the system to adapt to varying load conditions without requiring a single overly robust design. This segmentation enables weight reduction while maintaining structural integrity under different operational scenarios.
Solution Approach 2:
The bogie beams are designed with independent pivoting capability about their mounting axes, transforming the static rigid structure into a dynamic system. This allows the landing gear to automatically adjust its configuration in response to varying wheel loads, tyre pressures, and runway conditions, optimizing weight distribution and reducing the need for excessive structural reinforcement.
2Reliability
If single bogie beam with common axle is used, then device complexity is reduced, but reliability decreases due to inability to isolate braking systems
Solution Approach 1:
The braking systems are segregated onto separate bogie beams, creating independent failure zones. If one braking system fails or requires maintenance, the other bogie beam and its braking system continue to function normally. This segmentation of critical systems enhances overall reliability without requiring a complete redesign of the landing gear structure.
Solution Approach 2:
The dual bogie beam configuration acts as an intermediary structure that physically separates and isolates critical braking systems. This intermediate structural arrangement allows each braking system to operate independently while maintaining overall system functionality, providing a safety buffer against single-point failures.
3Adaptability or versatility
If rigid bogie beam structure is used, then manufacturing precision is easier to achieve, but adaptability decreases when accounting for tyre wear and pressure variations
Solution Approach 1:
The introduction of flexible bearing regions and spherical bearings enables the rigid bogie beam structure to dynamically adapt to varying tyre conditions. The flexible bearing regions allow for controlled movement and adjustment, compensating for tyre wear and pressure variations without requiring complex adjustable mechanisms or sacrificing manufacturing precision in the primary structural components.
Solution Approach 2:
The system allows for parameter changes in the bearing regions while maintaining fixed precision in the bogie beam structure itself. The flexible bearing regions can accommodate variations in wheel position and orientation caused by tyre conditions, effectively decoupling the precision requirements of the structural beams from the adaptability needs of the wheel support system.
4Weight of moving object
If bogie beams are designed for worst-case load distribution, then strength is sufficient, but weight increases due to excessive fatigue loading assumptions
Solution Approach 1:
By segmenting the landing gear into two independent bogie beams with independent pivoting capability, the system distributes and isolates fatigue loads more effectively. Each bogie beam experiences reduced and more uniform loading conditions compared to a single rigid beam that must accommodate all worst-case scenarios simultaneously. This allows for optimized material usage and weight reduction while maintaining adequate fatigue resistance.
Solution Approach 2:
The dynamic pivoting capability of the bogie beams allows the system to naturally equalize wheel loading under varying operational conditions, preventing the development of excessive localized fatigue loads. This dynamic load equalization reduces the conservative fatigue loading assumptions required in static designs, enabling weight optimization while maintaining sufficient strength and durability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design reduces the overall weight of the landing gear by allowing predictable vertical load distribution, reducing tire strength requirements, and minimizing fatigue loading assumptions, while maintaining equal wheel loading and improving safety through independent axle movement and braking system segregation.
Implementation Method 1
The flexible or dynamic bearing region can comprise a spherical bearing. This enables the landing gear assembly to place the wheel rims on one side of the landing gear in contact with the ground in the event of their tyres deflating when the wheels on the other side are inflated.
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3
AI summary
An aircraft landing gear assembly (40) comprising: a first elongate bogie beam (42a) including a first bearing (44a) via which the first bogie beam is arranged to be pivotally mounted to an aircraft landing gear main strut and defining a first bogie pivot axis; a second elongate bogie beam (42b) including a second bearing (44b), defining a second bogie pivot axis, via which the second bogie beam is arranged to be pivotally mounted to the aircraft landing gear main strut in a side by side adjacent relationship with the first bogie pivot axis being coaxial with respect to the second bogie pivot axis; a first axle (50a) mounted at a first end region of the first bogie beam, the first axle defining a first wheel mounting portion on a first side of the first bogie beam for supporting a first wheel assembly; a second axle (48a) mounted at a second end region of the first bogie beam, the second axle defining a second wheel mounting portion on the first side of the first bogie beam for supporting a second wheel assembly; a third axle (50b) mounted at a first end region of the second bogie beam, the third axle defining a third wheel mounting portion on a second side of the second bogie beam for supporting a first wheel assembly, the second side facing away from the first bogie beam; and a fourth axle (48b) mounted at a second end region of the second bogie beam, the fourth axle defining a fourth wheel mounting portion on the second side of the bogie beam for supporting a fourth wheel assembly, such that the first and second bogie beams can independently pivot about the respective bogie pivot axes in order to place a wheel rim of a wheel assembly in contact with the ground in the event of a tyre of the wheel assembly deflating.