Vehicle Pneumatic Spring With Elastomer Insert for Progressive Support
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Solution Overview
Problem
Pneumatic springs for vehicle suspensions exhibit increased hysteresis at high speeds and lack sufficient support during intermediate stages of compression, leading to unpredictable behavior and increased rigidity at the end of stroke, which is not addressed by existing solutions that either reduce available stroke or increase initial pressure.
Innovation Solution
A closed-cell elastomer body is integrated within the compression chamber, allowing for elastic and viscous deformation, which adjusts the spring's behavior to provide consistent support without increasing base pressure, reducing hysteresis, and maintaining available stroke length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid volume spacer is introduced into the compression chamber to increase end-of-stroke support, then the elastic behavior of the suspension is stiffened at the end of stroke, but the available volume of air/gas is decreased and the stroke available for the piston is reduced
Solution Approach 1:
The patent employs a flexible diaphragm instead of a rigid volume spacer. The diaphragm is made of elastomeric material that can deform elastically under compression, providing progressive resistance. This flexible membrane allows the piston to maintain full stroke availability while the diaphragm itself provides the necessary end-of-stroke support through its elastic properties and gradual deformation characteristic.
Solution Approach 2:
The patent changes the physical state and properties of the support mechanism from rigid to flexible. By using an elastomeric diaphragm with specific material properties (elastic modulus, thickness, geometry), the system achieves progressive stiffening during compression without permanently reducing the available volume or stroke. The diaphragm's deformation characteristics provide variable support that increases with compression level.
2Force
If the initial compression pressure is increased to provide greater support in the intermediate stages of the stroke, then the elastic force is increased at all stages of the stroke, but the suspension becomes excessively rigid at the end of stroke
Solution Approach 1:
The patent introduces a dynamic support mechanism through the elastomeric diaphragm that adapts its stiffness during the compression stroke. At intermediate stages, the diaphragm remains relatively flexible, providing gentle support. As compression progresses toward the end of stroke, the diaphragm deforms more significantly, increasing its resistance and providing progressive stiffening. This dynamic behavior eliminates the need for high initial pressure while avoiding excessive end-of-stroke rigidity.
Solution Approach 2:
The diaphragm undergoes periodic deformation cycles during suspension operation, flexing during compression and recovering during extension. This cyclic deformation allows the diaphragm to provide variable support characteristics - softer during early compression, progressively stiffer toward full compression - creating a more natural suspension feel without requiring uniformly high pressure throughout the stroke.
3Loss of energy
If the displacement of the rod is faster, then less energy is transferred to the outside by the system, but the hysteresis of the spring decreases in the stroke/pressure cycle at high speeds
Solution Approach 1:
The patent uses a composite structure combining the pneumatic system with an elastomeric diaphragm material. The elastomeric material exhibits viscoelastic properties that provide consistent hysteresis across different compression speeds. This composite approach (gas spring + elastomeric membrane) creates a more predictable overall behavior compared to gas springs alone, where the elastomer's material properties dominate the high-speed response and reduce the adiabatic effect variability.
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 greater support during compression while maintaining a consistent force at high speeds, reducing hysteresis and making the pneumatic suspension behavior more predictable, similar to a steel helical spring, with improved adhesion and reduced sudden nervousness during high-speed impacts.
Implementation Method 1
the closed-cell structure of the elastomer determines a substantially elastic deformation
Implementation Method 2
associated with a viscous behaviour, sensitive in the spring expansion and elongation stage
Implementation Method 3
reducing the increase in the elastic hysteresis of the spring as speeds increase
Data Source
Figure 1a~1b
Figure 2a~2
Figure 2b
AI summary
Pneumatic spring for vehicle suspensions comprising, a compression chamber (1) inside a cylinder (2) provided with a first external attachment point (4) and a sliding pneumatic piston (3) with a pressure seal in the chamber, comprising a closed cell expanded elastomer body (7) free to move inside the compression chamber (1).