Elastically Deformable Pin Joint Assembly for Aircraft Landing Gear
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Solution Overview
Problem
Aircraft pin joint assemblies for retractable landing gear experience increased weight and manufacturing costs due to the need to accommodate lug deflections, which require oversized components to handle load deflections, thereby affecting fuel efficiency.
Innovation Solution
The pin joint assembly incorporates elastically deformable retaining elements and bolts that absorb lug deflections, reducing the load transmitted to the joint, allowing for smaller and lighter components with equivalent or improved load-carrying capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the pin joint assembly uses rigid retaining elements and bolts to accommodate lug deflections, then the load carrying capability is sufficient, but the weight of the assembly increases significantly
Solution Approach 1:
The patent changes the physical state of the retaining elements from rigid to elastic by selecting materials with appropriate elastic moduli. The retaining elements are designed with elastic properties that allow them to deform under load, absorbing deflection forces without requiring oversized rigid components. This parameter change enables weight reduction while maintaining load carrying capability.
Solution Approach 2:
The patent employs composite construction by combining the joint pin (typically metal) with elastic retaining elements made from elastomeric or polymeric materials. This composite approach allows each component to perform its optimal function - the metal pin provides structural support while the elastic retainers absorb deflection loads, achieving weight reduction without compromising strength.
2Strength
If oversized components are used to handle lug deflection loads, then the load carrying capability is sufficient, but the manufacturing cost increases
Solution Approach 1:
The patent changes the mechanical properties of the retaining elements from rigid to elastic, which fundamentally alters the design approach. Instead of designing oversized rigid components to withstand deflection forces, the solution uses properly sized elastic components that naturally accommodate deflections through material deformation. This reduces manufacturing complexity and cost while maintaining adequate load carrying capability.
3Stability of the object's composition
If rigid pin joint components are used, then the structural integrity is maintained, but the weight reduction opportunity is lost
Solution Approach 1:
The patent uses composite materials combining rigid metal components (joint pin, lugs) with elastic polymer or elastomeric retaining elements. This composite structure maintains the structural integrity of the rigid framework while the elastic components provide compliance to reduce weight. The rigid components maintain geometric stability while the elastic retainers absorb energy and accommodate deflections.
Solution Approach 2:
The patent incorporates flexible elastic retaining elements that function similarly to flexible shells or films in absorbing and distributing loads. These elastic components can deform to accommodate lug deflections while maintaining the overall structural integrity of the pin joint assembly, enabling weight reduction without compromising stability.
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 achieves a significant weight reduction of approximately 15kg per dual stay landing gear assembly, enhancing fuel efficiency and reducing manufacturing costs by using compliant materials and thinner retaining elements.
Implementation Method 1
at least a portion of the pin joint is elastically deformable
Data Source
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AI summary
A pin joint assembly for an aircraft landing gear comprising: an elongate joint pin (106); at least one first lug (102,102a) through which the joint pin passes; and at least one second lug (104,104a) through which the joint pin passes; wherein the joint pin includes first and second retaining elements (107) located at opposite ends of the joint pin and arranged to maintain the location of the joint pin relative to the first and second lugs, wherein at least portion of the pin joint is elastically deformable.