Frequency-Dependent Shock Absorber Valve for Ride Isolation
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Solution Overview
Problem
Conventional hydraulic dampers lack effective frequency-dependent damping characteristics during both compression and rebound strokes, particularly in isolating vehicle bodies from unwanted disturbances caused by varying road frequencies.
Innovation Solution
A hydraulic shock absorber with a frequency-dependent valve system that includes a pressure tube, a reserve tube, and a piston assembly, featuring an axially slidable spool valve that adjusts fluid flow based on movement frequency, providing minimal damping during high-frequency movements and increased damping during low-frequency movements by controlling fluid flow between the working chamber and the reservoir.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional hydraulic dampers use fixed damping characteristics, then the structure is simple, but the ability to isolate vehicle body from disturbances of varying frequencies is poor
Solution Approach 1:
The patent applies dynamics by making the damping characteristics changeable based on operating conditions. The frequency-dependent valve system dynamically adjusts damping force according to the frequency of road inputs, transitioning from fixed to variable damping properties to achieve optimal isolation across different frequency ranges.
Solution Approach 2:
The patent changes the damping parameter based on frequency. The valve system modifies flow resistance and damping coefficients according to the frequency of piston movement, allowing the damper to provide appropriate damping levels for different road conditions without requiring multiple separate systems.
2Object-affected harmful factors
If frequency dependent damping devices provide softer damping characteristics with higher frequency road inputs, then isolation effectiveness is improved, but damping force during low frequency movements is reduced
Solution Approach 1:
The patent applies local quality by providing different damping characteristics for different frequency ranges. The valve system creates localized flow paths and resistance zones that selectively affect high-frequency movements differently from low-frequency movements, allowing optimized performance for each frequency band independently.
Solution Approach 2:
The frequency-dependent valve system dynamically adjusts damping force based on movement frequency. During high-frequency inputs, the valve provides softer damping to isolate the vehicle body, while during low-frequency compression, the valve maintains adequate damping force to control body motion and support vehicle weight.
3Ease of operation
If the spool valve allows fluid flow during high frequency compression stroke, then damping is reduced for comfort, but fluid flow control precision is compromised
Solution Approach 1:
The spool valve acts as an intermediary element that mediates between the need for comfort and flow control precision. By positioning the spool valve in a specific location within the hydraulic circuit and designing its geometry appropriately, the system achieves both comfort during high-frequency inputs and adequate flow control through the intermediary valve mechanism.
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 enables a smooth transition from soft to firm damping conditions, effectively isolating the vehicle body from disturbances across a range of road frequencies, enhancing ride quality by providing optimal damping during both compression and rebound strokes.
Implementation Method 1
a biasing element for biasing the interface member into contact with the valve seat plate
Implementation Method 2
fluid pressure to urge the interface member away from the valve seat plate
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 pressure tube is disposed within a reserve tube and a working fluid reservoir is formed between the pressure tube and the reserve tube. The piston assembly divides the pressure tube into an upper working chamber and a lower working chamber. A base valve assembly controls a flow of working fluid between the working fluid reservoir and the lower working chamber. The base valve assembly includes a frequency dependent valve system that provides an increased level of damping for each compression stroke of the piston assembly during low frequency movements of the shock absorber. A lesser level of damping is provided for each compression stroke during high frequency movements of the shock absorber.