Shape Memory Spring Tire Assembly With Bump Stop Load Support
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Solution Overview
Problem
Existing non-pneumatic spring tires face limitations in load carrying capacity, susceptibility to permanent damage when deformed, and excessive weight due to their design using spring steel, which is not ideal for improved performance.
Innovation Solution
A wheel assembly incorporating shape memory alloys (SMAs) for the outer and inner rim portions, tread elements, and bump stop assemblies, allowing for variable stiffness, improved traction, and load distribution across the entire wheel diameter, enabling superior load carrying, flotation, and climbing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If spring steel is used for the tire structure, then the tire provides structural support and load carrying capacity, but the tire becomes very heavy and susceptible to permanent damage when deformed
Solution Approach 1:
The patent changes the material parameter from conventional spring steel to shape memory alloy (SMA), which fundamentally alters the mechanical properties. SMAs provide comparable strength and load carrying capacity but with reduced weight and enhanced elasticity, eliminating permanent deformation. The phase transformation characteristics of SMAs enable the tire to recover from large deformations without permanent damage.
Solution Approach 2:
The tire employs a composite structure combining shape memory alloy springs with other materials optimized for specific functions. This composite approach allows the SMA to provide the primary load-bearing and elastic recovery functions while other materials handle specific wear or structural requirements, achieving optimal weight-strength balance.
2Strength
If spring steel is used for the tire structure, then the tire provides structural support, but the tire is prone to permanent damage when deformed
Solution Approach 1:
The patent changes the material parameter from conventional spring steel to shape memory alloy (SMA), which fundamentally alters the mechanical properties. SMAs provide comparable strength and load carrying capacity but with reduced weight and enhanced elasticity, eliminating permanent deformation. The phase transformation characteristics of SMAs enable the tire to recover from large deformations without permanent damage.
Solution Approach 2:
The bump stop assembly acts as a preventive cushioning mechanism that engages before excessive deformation can cause damage to the tire structure. By providing early mechanical intervention when the tire encounters obstacles or extreme deflection, the bump stop prevents conditions that would lead to permanent damage or failure of the SMA elements.
3Strength
If the tire is designed to carry heavy loads, then the load carrying capacity increases, but the tire weight increases
Solution Approach 1:
The patent changes the material parameter from conventional spring steel to shape memory alloy (SMA), which fundamentally alters the mechanical properties. SMAs provide comparable strength and load carrying capacity but with reduced weight and enhanced elasticity, eliminating permanent deformation. The phase transformation characteristics of SMAs enable the tire to recover from large deformations without permanent damage.
Solution Approach 2:
The tire employs dynamic shape memory alloy elements that can change their stiffness characteristics based on applied load and temperature. Under heavy loads, the SMA elements transition to a stiffer state to support the increased weight, while under normal conditions they remain more compliant, optimizing the weight-strength balance across different operating conditions.
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
The use of SMAs in the wheel assembly enhances load carrying capacity, traction, and climbing ability while maintaining a lightweight design, preventing further deflection through a flexible bump stop mechanism and distributing ground pressure evenly.
Implementation Method 1
The outer main body portion includes a plurality of outer shape memory elements having first and second opposite ends. The first end of each outer shape memory element is secured or connected to the first outer rim portion and the second end of each outer shape memory element is secured or connected to the second outer rim portion.
Data Source
AI summary
A wheel assembly that includes an outer rim assembly with a first outer rim portion, a second outer rim portion, and a plurality of outer cross members extending between the first and second outer rim portions, a tire assembly secured to the outer rim assembly, and at least a first bump stop assembly. The tire assembly includes an outer main body portion that includes first and second outer side wall portions and an outer contact portion extending transversely between the first and second outer side wall portions. The first bump stop assembly includes a first inner rim portion, a second inner rim portion and an inner main body portion. The inner main body portion includes first and second inner side wall portions and an inner contact portion extending transversely between the first and second inner side wall portions. The inner contact portion is coupled to the outer contact portion.