Frequency-Dependent Passive Valve for Shock Absorber Damping
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Solution Overview
Problem
Conventional hydraulic dampers lack effective frequency-dependent passive valving systems that provide softer damping characteristics during both rebound and compression strokes, particularly for high-frequency road inputs, which affects the isolation of vehicle bodies from unwanted disturbances.
Innovation Solution
A frequency-dependent hydraulic damper with a passive valving system that includes a spool valve assembly and disc pack, allowing for adjustable damping by altering the preload between valve components based on movement frequency, enabling softer damping during both extension/rebound and compression strokes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional hydraulic dampers use fixed damping characteristics, then the structure is simple, but the ability to isolate vehicle body from high-frequency road inputs is poor
Solution Approach 1:
The patent implements a frequency-dependent passive valving system where the damping characteristics dynamically change based on the frequency of road inputs. The spool valve assembly with spring-loaded mechanism automatically adjusts valve opening based on frequency, providing softer damping for high-frequency inputs without requiring external control systems or complex active electronics.
Solution Approach 2:
The patent changes the damping parameter (damping force) as a function of input frequency. The passive valving system uses spring preload and spool valve geometry to create frequency-dependent damping characteristics, where the valve opening and damping force vary automatically with the frequency of piston movement, eliminating the need for fixed damping settings.
2Ease of operation
If frequency-dependent damping devices are implemented, then softer damping for high-frequency inputs is achieved, but the device complexity increases
Solution Approach 1:
The patent employs a self-regulating passive valving system where the spool valve and spring assembly automatically adjust damping characteristics based on the frequency of road inputs. The system uses the kinetic energy and pressure from the hydraulic fluid itself to actuate the valve mechanism, eliminating the need for external power sources, sensors, or control systems while achieving frequency-dependent softer damping.
Solution Approach 2:
The patent uses hydraulic principles to create the frequency-dependent damping effect. The spool valve assembly utilizes hydraulic pressure from the moving piston to overcome spring preload and open the valve, allowing frequency-dependent fluid flow control. The hydraulic system itself provides the actuating force for the valve mechanism, integrating the damping control function into the existing hydraulic circuit.
3Reliability
If passive valving system is added to provide frequency-dependent damping, then high-frequency isolation improves, but manufacturing complexity increases
Solution Approach 1:
The patent segments the valving system into distinct functional components: the spool valve assembly, spring-loaded mechanism, and hydraulic passages. This modular segmentation allows each component to be manufactured and tested separately, then assembled into the complete frequency-dependent damping system, simplifying the manufacturing process while maintaining reliable performance.
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 solution provides improved isolation of the vehicle body from disturbances by dynamically adjusting damping characteristics in response to high-frequency inputs, enhancing comfort and rolling performance during both stroke movements.
Implementation Method 1
A frequency-dependent hydraulic damper with a passive valving system that includes a spool valve assembly and disc pack, allowing for adjustable damping by altering the preload between valve components based on movement frequency
Implementation Method 2
A first valving system is incorporated for generating damping force during the extension or rebound stroke of the hydraulic damper and a second valving system is incorporated for generating damping force during the compression stroke of the hydraulic damper
Implementation Method 3
The solution provides improved isolation of the vehicle body from disturbances by dynamically adjusting damping characteristics in response to high-frequency inputs, enhancing comfort and rolling performance during both stroke movements
Implementation Method 4
a frequency dependent passive valving system that provides softer damping characteristics with high frequency road inputs in rebound or compression strokes
Data Source
AI summary
A shock absorber has a pressure tube with a piston assembly slidably disposed within the pressure tube and attached to a piston rod. The piston assembly divides the pressure tube into an upper working chamber and a lower working chamber. The piston assembly includes a frequency dependent valve assembly attached to the piston rod which defines a housing attached to the piston rod and a spool valve assembly. The spool valve assembly includes a spool valve and a bypass valve assembly that controls fluid flow through bypass passage that bypasses the piston assembly.