Damping Air Spring and Shock Absorber for Heavy-Duty Axle Suspension
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Solution Overview
Problem
Heavy-duty vehicle axle/suspension systems face challenges in providing optimal damping across a wide range of frequencies, leading to increased transmissibility of forces, misting, and premature wear of components, while standard shock absorbers add weight and complexity, and prior art air springs with damping features offer inadequate damping at higher frequencies.
Innovation Solution
A combination of a damping air spring and an optimized shock absorber, where the air spring provides damping at lower frequencies and the shock absorber is tuned for optimal damping at higher frequencies, reducing transmissibility and weight, and enabling the vehicle to haul more cargo.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If standard shock absorbers are used to provide damping, then damping force is improved, but weight and device complexity increase
Solution Approach 1:
The damping function is segmented between two components: the air spring handles low-frequency damping (body bounce mode around 1.8 Hz) while the shock absorber handles high-frequency damping (wheel hop mode around 13 Hz). This segmentation allows each component to be optimized for its specific frequency range, reducing the overall weight and complexity compared to using a heavy-duty shock absorber for all frequencies.
Solution Approach 2:
The air spring is modified with damping features that change its operational parameters based on frequency. The damping coefficient of the air spring is optimized for low-frequency operation, while the shock absorber is tuned for high-frequency operation. This parameter differentiation allows lighter components to be used instead of a single heavy shock absorber covering all frequencies.
2Force
If shock absorber damping is increased at higher frequencies, then damping is improved, but transmissibility of forces increases and misting occurs
Solution Approach 1:
The frequency spectrum is segmented into two ranges: low-frequency damping is provided by the air spring, and high-frequency damping is provided by the shock absorber. This segmentation prevents the shock absorber from being overloaded with excessive damping requirements across all frequencies, thereby reducing transmissibility and preventing misting.
Solution Approach 2:
The damping characteristics of the system are made dynamic by having different damping mechanisms active at different frequencies. The air spring provides variable damping that is effective at low frequencies, while the shock absorber provides damping at high frequencies. This dynamic approach allows the system to adapt to different operating conditions without causing harmful effects.
3Force
If air spring damping features are added, then low-frequency damping is improved, but damping at higher frequencies remains inadequate
Solution Approach 1:
The invention merges two damping mechanisms: an air spring with damping features for low-frequency operation and a shock absorber for high-frequency operation. The air spring's damping features (such as adjustable orifices or valves) provide optimized damping at low frequencies, while the shock absorber supplements this by providing damping at high frequencies where the air spring is inadequate.
Solution Approach 2:
The combined air spring-shock absorber system serves multiple functions: the air spring provides both suspension and low-frequency damping, while the shock absorber provides high-frequency damping. This multi-functional approach ensures comprehensive damping coverage across the entire frequency spectrum, improving reliability without requiring a single component to perform all functions.
4Force
If heavy-duty shock absorbers are used to provide comprehensive damping, then damping across all frequencies is improved, but vehicle cargo capacity is reduced
Solution Approach 1:
The damping function is segmented between the air spring and shock absorber, with each component optimized for specific frequency ranges. This segmentation allows the use of lighter components compared to a single heavy-duty shock absorber that would be required to provide comprehensive damping across all frequencies, thereby reducing overall vehicle weight and increasing cargo capacity.
Solution Approach 2:
The damping parameters are changed and optimized for different frequency ranges by using two separate components. The air spring is tuned for low-frequency damping while the shock absorber is tuned for high-frequency damping. This parameter optimization allows lighter components to be used, reducing vehicle weight and increasing cargo capacity.
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 combination provides improved damping characteristics across the entire spectrum of critical frequencies, increasing the durability and life of suspension system components, maintaining a soft ride, and reducing the need for heavy shock absorbers, thus enhancing the vehicle's cargo capacity and operational efficiency.
Implementation Method 1
The air spring includes a bellows and a piston. The top end of the bellows is sealingly engaged with a bellows top plate... The piston is generally cylindrical-shaped and includes a continuous generally stepped sidewall... The piston top plate, sidewall and bottom plate define a piston chamber having an interior volume... The bellows, top plate and piston top plate define a bellows chamber having an interior volume
Implementation Method 2
The bellows is typically formed from rubber or other flexible material... The larger the air volume of the air spring, the lower the spring rate of the air spring
Implementation Method 3
The shock absorber typically includes a cylinder that is filled with fluid. A plunger with a diaphragm mounted on its end is disposed longitudinally within the fluid filled cylinder... The movement of the plunger and diaphragm through the fluid filled cylinder results in viscous damping of the axle/suspension system
Data Source
AI summary
A damping air spring and shock absorber combination for heavy-duty vehicle axle/suspension systems includes a damping air spring and a shock absorber both operatively attached to the axle/suspension system. The damping air spring primarily provides damping to the axle/suspension system over a first range of frequencies. The shock absorber primarily provides damping to the axle/suspension system over a second range of frequencies. The first range of frequencies is from about 0.0 Hz to about 6.0 Hz and the second range of frequencies is from about 0.0 Hz to about 13.0 Hz.