Vented Air-Spring Bump Stop With Variable-Density Infill
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bump stops for vehicle suspension systems are inadequate as they fail to properly address the dynamic nature of suspension travel, often leading to jarring impacts, insufficient protection, and susceptibility to cracking and high costs.
Innovation Solution
A bump stop design featuring an outer shell that retains air and vents it through specifically tuned ports, combined with a variable-density internal structure created using 3D printing, allowing for adjustable stiffness and resistance to cracking, while being mountable in existing factory locations without requiring tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid rubber block is used as a bump stop, then the suspension travel is limited, but a jarring impact is felt by the vehicle operator due to the stiff material
Solution Approach 1:
The bump stop utilizes a porous foam material structure that allows controlled compression and energy absorption. The porous structure enables the material to deform progressively under load, reducing impact transmission to the vehicle operator while maintaining effective suspension travel limitation. The cellular structure of the foam provides multiple compression stages that cushion the impact rather than transmitting it as a sharp jarring force.
Solution Approach 2:
The invention employs composite construction combining an outer shell with an internal foam structure. This composite approach integrates the protective function of the shell with the energy-absorbing characteristics of the foam material, achieving both reliable suspension limitation and reduced impact transmission through the combined material system.
2Stability of the object's composition
If multi-cellular polyurethane is used as a bump stop, then the material provides uniform stiffness, but it lacks sufficient suspension protection due to inability to offer variable stiffness
Solution Approach 1:
The bump stop features variable density distribution within the foam structure, creating regions of different stiffness characteristics. This local variation in material density allows the bump stop to provide progressive resistance during compression - softer initial contact for comfort and firmer resistance at full compression for adequate suspension protection, replacing the uniform stiffness of multi-cellular polyurethane.
3Stability of the object's composition
If dual-durometer rubber bump stops are used, then progressive stiffness is offered during travel, but they do not offer dynamic response based on the rate of impact
Solution Approach 1:
The foam-based bump stop provides dynamic response characteristics that adapt to the rate of compression. During rapid impact events, the foam cells compress and vent air through pores at rates proportional to the impact speed, creating a damping effect that responds dynamically to different compression rates. This replaces the static dual-durometer approach with a dynamically adaptive material response.
Solution Approach 2:
The foam structure incorporates air venting through its porous network, creating a pneumatic damping mechanism. As the foam compresses during suspension travel, trapped air must escape through the porous structure, providing resistance proportional to the compression rate. This pneumatic effect enables dynamic response to impact rate without requiring complex mechanical mechanisms.
4Reliability
If rubber bump stops are used, then the bump stop limits suspension travel, but crack propagation occurs quickly through the material causing complete failure
Solution Approach 1:
The porous foam structure inherently resists crack propagation compared to solid rubber. The cellular structure distributes stress throughout the material and provides multiple pathways for energy dissipation, preventing the development of continuous crack paths. This extends the service life of the bump stop while maintaining its suspension limitation function, as cracks cannot easily propagate through the fragmented foam cell structure.
5Adaptability or versatility
If hydraulic bump stops are used, then dynamic damping is provided, but they require cutting or welding onto the frame and cost five to ten times more than rubber bump stops
Solution Approach 1:
The foam-based bump stop provides a cost-effective alternative to expensive hydraulic systems, accepting that the simpler foam construction has a limited service life. The material is designed to be replaced rather than repaired, offering economical dynamic damping for applications where hydraulic systems would be prohibitively complex and expensive, trading longevity for simplicity and affordability.
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 solution provides a dynamic response to suspension compression rates, offering adjustable stiffness, enhanced durability by preventing crack propagation, and cost-effectiveness by being installable in standard mounting locations without additional modifications or tools.
Implementation Method 1
The outer shell retains air within the bump stop. Air is vented through the one or more ports.
Implementation Method 2
Air is vented through the one or more ports.
Data Source
AI summary
A bump stop for a suspension system. The bump stop comprises an outer shell around an internal structure; and one or more ports. The outer shell retains air within the bump stop. Air is vented through the one or more ports. The internal structure includes a variable density infill structure. The outer shell is detached from the internal structure at one or more locations. A core includes sidewalls with accordion-style bellows. A base region has a higher density than the internal structure.