Hydraulic Springing Assembly with Variable Flow Resistances
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Solution Overview
Problem
Current hydropneumatic suspension systems face challenges in rapidly adjusting spring rate and damping to respond to vibration excitations and varying external influences, such as ground conditions and load, with existing solutions requiring complex and inefficient mechanisms.
Innovation Solution
The implementation of two double-acting hydraulic cylinders with permanently connected piston and piston rod chambers, featuring crosswise variable flow resistances and a control device that adjusts these resistances based on ambient conditions, allowing for quick switching between hard and soft states of springing and damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If adjustable dampers are used to adjust spring rate and damping, then the suspension can adapt to external influences, but the adjustment mechanism becomes complex and the response time is insufficient
Solution Approach 1:
The patent uses a hydraulic system with a double-acting cylinder connected to two pressure accumulators (one for each chamber). By opening or closing valves, hydraulic fluid can be transferred between chambers, rapidly changing the spring rate and damping characteristics without complex mechanical adjustment mechanisms. This hydraulic approach enables quick adaptation to varying external conditions.
Solution Approach 2:
The invention changes the physical parameters of the suspension system by transferring hydraulic fluid between chambers. By varying the volume of hydraulic fluid in each chamber through valve control, the spring rate and damping coefficients are dynamically adjusted. This parameter change approach allows rapid adaptation without mechanical complexity.
2Reliability
If double-acting cylinders with separate oil circuits are used, then preload can be applied and spring rate dependence is reduced, but the implementation effort increases
Solution Approach 1:
The patent merges two separate oil circuits into a single integrated system where both chambers share common components (pressure accumulators, valve assembly, hydraulic fluid reservoir). This consolidation maintains the reliability benefits of double-acting cylinders with preload capability while significantly reducing implementation effort through component sharing and simplified architecture.
Solution Approach 2:
The hydraulic system is designed with multi-functionality: the same pressure accumulators and valve assembly serve both chambers simultaneously. The system can operate in multiple modes (both chambers connected to accumulators, one chamber isolated, fluid transfer between chambers) using a unified architecture, reducing overall complexity while maintaining reliability.
3Device complexity
If chambers are constantly connected to pressure accumulators with fixed flow resistance, then the system is simple, but the spring rate and damping cannot be rapidly adjusted
Solution Approach 1:
The invention introduces dynamic valve control that allows the system to switch between different operational states. The valves can rapidly open or close to connect or isolate chambers from pressure accumulators and to enable fluid transfer between chambers. This dynamic control provides fast adjustment of spring rate and damping while maintaining relative system simplicity through binary valve states.
Solution Approach 2:
The system uses periodic or on-demand valve actuation to adjust suspension characteristics. Rather than continuous adjustment, the valves are activated at specific moments to transfer fluid between chambers or connect/discharge to accumulators, achieving rapid adaptation with simple periodic control actions.
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 solution enables rapid and manageable adjustment of spring rate and damping, effectively mitigating unwanted movements and adapting to changing conditions, particularly suitable for systems with small load changes like vehicle operator stations.
Implementation Method 1
The piston chambers and piston rod chambers of which are each permanently connected to pressure accumulators assigned to them
Implementation Method 2
Two variable flow resistances are arranged crosswise between the piston chamber of one hydraulic cylinder and the piston rod chamber of the other cylinder and vice versa
Data Source
Figure 1
AI summary
The hydraulic suspension arrangement comprises a double-acting hydraulic cylinder (10) with a piston area (12) and a piston rod area (14). An accumulator (26) is provided, which is constantly connected with the piston area and another accumulator (30) is provided, which is constantly connected with the piston rod area. The piston area and the piston rod area are connected or connectable among each other by a changeable flow resistance. An independent claim is included for a vehicle which comprises a chassis and an operator station.