Switchable Spring-Damper System for Vehicle Suspension
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Solution Overview
Problem
Existing spring-damper systems for vehicle wheel suspension are inefficient due to the need for manual and time-consuming adjustments of spring rates, which can cause damage during switching and require the vehicle to be unloaded, and are often costly and space-intensive.
Innovation Solution
A spring-damper system with a support spring, a fluid-filled pressure generator, and an additional spring unit, where the switching device controls fluid flow to change the spring constant without mechanical locking, allowing for immediate and loaded switching by altering the fluid flow to lock or release the additional spring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mechanical locking element is used to block the spring during switching, then the spring constant can be adjusted between different values, but the switching process requires time for the locking element to move along a path and cannot occur immediately
Solution Approach 1:
The patent replaces the mechanical locking system with a fluid-based control system. A piston moves within a cylinder filled with viscous fluid, and the fluid's resistance to flow through restricted passages provides the locking effect without requiring mechanical locking elements to travel along paths. This substitution eliminates the time delay associated with mechanical locking element movement while maintaining the ability to block and release the spring.
Solution Approach 2:
The invention uses a hydraulic system where viscous fluid in a cylinder resists the movement of a piston. The fluid flow is restricted through specific passages, creating hydraulic resistance that locks the piston in position. By controlling fluid flow through valves or changing passage restrictions, the system can rapidly transition between locked and unlocked states, enabling immediate spring constant switching without mechanical locking element movement delays.
2Adaptability or versatility
If a mechanical locking element moves to block the spring during switching, then the spring constant can be changed, but damage can occur to the locking element or spring during the switching time under load
Solution Approach 1:
The patent eliminates mechanical locking elements that are subject to impact loads and potential damage. Instead, a piston constrained by viscous fluid resistance provides the blocking function. The fluid's viscosity naturally limits the piston's movement speed, preventing sudden impacts that could damage mechanical components, while still providing sufficient blocking force to maintain the desired spring constant.
Solution Approach 2:
The viscous fluid in the cylinder acts as a cushioning medium that prevents sudden movements and impacts. As the piston attempts to move during switching, the fluid's resistance smoothly decelerates the piston, preventing impact damage to the piston, cylinder walls, or spring. This beforehand cushioning effect is built into the system through the fluid's inherent viscous properties.
3Productivity
If the spring constant is switched while the vehicle is loaded, then operational continuity is maintained, but in prior art systems the switching process cannot occur immediately due to mechanical locking element movement requirements
Solution Approach 1:
The patent replaces the mechanical locking system with a fluid-based system that can respond immediately to switching commands. The piston's position is controlled by fluid flow restrictions rather than mechanical locking element movement. This allows the system to switch spring constants instantly even under load, maintaining operational continuity without the time delays inherent in mechanical locking systems.
Solution Approach 2:
The system uses a dynamically controllable fluid flow restriction mechanism that can rapidly change the piston's blocking position. By adjusting the fluid passage restrictions or valve positions, the system can adapt the piston's position in real-time, enabling immediate spring constant switching while the vehicle is loaded and moving, thus maintaining operational continuity.
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
Enables rapid and cost-effective adjustment of spring constants under load, reducing the risk of damage and eliminating the need for unloading the vehicle, while maintaining a compact design.
Implementation Method 1
a pressure generator acting parallel to the support spring and filled with a fluid
Implementation Method 2
a compression or expansion of the support spring leads to a movement on the pressure generator
Implementation Method 3
a pressure is generated in the pressure cylinder by the compression of the support spring and the movement of the piston rod into the pressure generator
Data Source
Figure 1~3
Figure 4
Figure 5~7
AI summary
The invention relates to a spring-damper system for a wheel suspension of a motor vehicle, comprising a supporting spring (10) having a spring constant kT, a pressure generator (20), which acts parallel to the supporting spring (10) and which is filled with a fluid, an additional spring unit (30) having an additional spring (31), which has a spring constant kZ, a switching device (40) having a blocking position and a release position for switching the additional spring (31), and a damper (60) acting parallel to the supporting spring (10), wherein the switching device (40) blocks the additional spring (31) in the blocking position, and in the release position the additional spring (31) acts parallel to the supporting spring (10) by means of the fluid.