Vehicle Vibration Damper With Stroke- and Frequency-Dependent Piston
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Solution Overview
Problem
Existing vibration dampers for vehicles either require complex active systems for adjustable damping or lack the ability to adapt to varying movement variables, leading to inefficiencies in frequency- and stroke-dependent damping.
Innovation Solution
A vibration damper design incorporating a stroke-dependent piston with a frequency-dependent valve, allowing for adjustable damping based on both piston stroke and vibration frequency without additional complexity or space, utilizing a common component for both compression and rebound stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If controlled shock absorbers with active electronic actuators are used to adjust damping characteristics, then adaptability to different situations is improved, but device complexity and installation space increase
Solution Approach 1:
The shock absorber uses the kinetic energy from the piston's own motion to drive the frequency-selective valve mechanism, eliminating the need for external power sources or electronic actuators. The valve automatically adjusts damping characteristics based on the piston's velocity and direction, making the system self-regulating without additional complexity.
Solution Approach 2:
The invention changes the damping parameter dynamically by varying the effective valve opening area based on piston velocity and stroke direction. The frequency-selective valve modifies the flow characteristics of the damping fluid through the piston, achieving adaptive damping by changing fluid flow parameters rather than mechanical structure parameters.
2Measurement precision
If frequency-dependent valves are added to achieve frequency-selective damping, then damping precision is improved, but device complexity increases
Solution Approach 1:
The frequency-selective valve functionality is merged into the existing piston structure. The valve components are integrated directly into the piston body, combining the damping function with the frequency-selective control function in a single element, thereby avoiding additional separate valve assemblies and reducing overall system complexity.
Solution Approach 2:
The piston serves multiple functions: it provides the primary damping action, houses the frequency-selective valve mechanism, and acts as the moving component that drives the valve operation. This multi-functionality eliminates the need for separate dedicated frequency-selective valve assemblies, reducing device complexity while maintaining precision.
3Ease of operation
If separate valve systems are used for compression and rebound stages, then damping control is improved, but installation space increases
Solution Approach 1:
A single frequency-selective valve system handles both compression and rebound damping control by responding to the direction and velocity of piston motion. The valve automatically adjusts its characteristics based on whether the piston is moving in compression or rebound, eliminating the need for separate valve assemblies for each stroke direction and reducing installation space.
Solution Approach 2:
The valve system is designed to dynamically adapt its characteristics based on the piston's motion parameters. The same physical valve structure provides different damping control for compression and rebound stages by utilizing the directional flow of damping fluid and the velocity-dependent forces acting on the valve components, achieving stage-specific control without separate hardware.
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 efficient frequency- and stroke-dependent damping in a single component, reducing complexity and installation space while improving damping performance across various vehicle movements.
Implementation Method 1
Hydraulic shock absorbers essentially consist of an oil-filled cylinder and a piston rod with a piston running inside it. When the piston rod (and thus the piston) moves axially relative to the cylinder, the oil must flow through narrow channels and valves in the piston. The resistance encountered by the oil creates pressure differences, which, via the contact surfaces, generate the damping forces.
Implementation Method 2
The resistance encountered by the oil creates pressure differences, which, via the contact surfaces, generate the damping forces.
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a vibration damper for a vehicle, comprising at least one cylinder tube forming a fluid chamber, in which a piston assembly is axially slidingly arranged and divides the cylinder tube into two working chambers, an upper and a lower working chamber, and wherein the piston assembly comprises an axially moveable main piston which is axially fixed to a piston rod that can move axially relative to the cylinder tube, and which has a piston valve influencing the fluid flow between the upper and lower working chambers, and wherein a further stroke-dependent piston is arranged on an axial extension of the piston rod in the direction of the cylinder base, which operates once a determined damper stroke is achieved, and wherein the stroke-dependent piston has a smaller diameter than the main piston and only operates when plunging into a smaller diameter of an inner casing surface, and wherein the stroke-dependent piston therefore has a stroke-dependent valve, and wherein the stroke-dependent piston also has a frequency-dependent valve in addition to the stroke-dependent valve.