Hydro-pneumatic Suspension with Series Coil Spring
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Solution Overview
Problem
Existing vehicle suspensions face challenges in balancing high load capacity and comfort, requiring compromises that are only partially addressed by traditional designs, and suffer from limitations in insulation and complexity, particularly with the use of fluidic dampers and hydro-pneumatic springs.
Innovation Solution
A suspension system featuring a hydro-pneumatic spring combined in series with a coil spring, acting as an energy dissipator, which eliminates the need for a traditional fluidic damper, providing adjustable damping through oil flow, heat exchange, and mechanical friction, and allows for independent adjustment of elastic modulus and preload force, ensuring safety and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a coil spring with high elastic modulus is used to increase load capacity, then the load capacity is improved, but the resonance frequency increases reducing comfort
Solution Approach 1:
The patent combines a coil spring and a gas spring into a unified suspension system where both elements work together. The coil spring provides high load capacity while the gas spring provides progressive elastic modulus and intrinsic damping, achieving both strength and comfort requirements simultaneously rather than compromising between them.
Solution Approach 2:
The gas spring performs multiple functions: it provides progressive elastic modulus to improve comfort, offers intrinsic damping capability to reduce vibrations, and enables adjustable ride height. This multi-functionality allows the system to achieve comfort goals without requiring additional dedicated components.
2Loss of energy
If a fluidic damper is added in parallel to increase damping, then the damping capability is improved, but the insulation features are limited at high frequencies
Solution Approach 1:
The patent uses a gas spring instead of a traditional fluidic damper. The gas spring provides progressive elastic modulus and intrinsic damping capability through gas compression and expansion, achieving effective damping without the high-frequency insulation limitations of fluidic dampers.
Solution Approach 2:
The gas spring provides progressively increasing elastic modulus as compression increases, allowing the system to adapt its stiffness characteristics based on the magnitude of suspension travel. This progressive characteristic improves high-frequency insulation while maintaining damping capability.
3Adaptability or versatility
If a hydro-pneumatic spring is used to vary elastic modulus, then the elastic modulus adjustment is improved, but the device complexity increases
Solution Approach 1:
The patent merges the functions of the coil spring, gas spring, and fluidic damper into a single integrated hydro-pneumatic spring assembly. This combination achieves variable elastic modulus and damping capabilities without requiring separate components, thereby reducing overall system complexity.
Solution Approach 2:
The hydro-pneumatic spring performs multiple functions simultaneously: it provides progressive elastic modulus, intrinsic damping, and ride height adjustment capabilities. This multi-functionality eliminates the need for separate dampers and adjustment mechanisms, reducing device complexity.
4Strength
If an air spring is used to provide high load capacity and adjustable features, then the load capacity and adjustability are improved, but the space requirement and safety risks increase
Solution Approach 1:
The patent nests the fluidic damper components within the gas spring structure. The piston and cylinder elements are integrated into the gas spring assembly, achieving compact packaging that reduces overall space requirements while maintaining all necessary functions.
Solution Approach 2:
The patent uses a coil spring as a backup safety element that can replace the gas spring if it fails. The coil spring is simpler, more robust, and less prone to leakage issues, providing a reliable fallback that reduces safety risks associated with air springs.
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 configuration enhances insulation at high frequencies, reduces structural complexity, and provides a high level of safety and flexibility, allowing for a wide range of load-transfer characteristics without the need for additional mechanical components, ensuring reliable operation and adaptability to various driving conditions.
Implementation Method 1
an elastic element, usually a coil spring, that reacts with a strength proportional to its deformation
Implementation Method 2
a damper, generally of the fluidic type, arranged in parallel to said spring that reacts with a force generally proportional to the moving speed of the suspension
Implementation Method 3
a device comprising a first section containing a gas, and a second section containing oil and separated from the first section through a transfer piston
Implementation Method 4
Said hydro-pneumatic spring, in the mentioned documents of known previous art - and depending on the type of suspension - either has the only task to change the ground clearance of the vehicle, or it has the task to vary the overall elastic modulus of the suspension
Data Source
Figure 1~2
Figure 3~4
AI summary
Suspension (1) for a wheeled vehicle provided with at least one wheel (50) and a frame (51), comprising at least one elastic element (5) functionally combinable between said at least one wheel (50) and said frame (51 ), characterized by comprising at least one hydro-pneumatic spring (7) functionally combined in series with said at least one elastic element (5) so that the equivalent spring modulus (Keq) of said at least one elastic element (5) and said at least one hydro-pneumatic spring (7) is variable as a function of the distance between said frame and said wheel, said at least one hydro- pneumatic spring being shaped and sized to behave also as an energy dissipator in series to said at least one elastic element.