Frequency Sensitive Shock Absorber Valve Assembly
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Solution Overview
Problem
Conventional shock absorbers struggle to simultaneously achieve ride comfort and adjustment stability due to damping force variations with speed and frequency changes, affecting performance across different road surface conditions.
Innovation Solution
A frequency-sensitive shock absorber design featuring a valve assembly with a piston valve and elastic pilot valves that adjust damping force based on frequency and speed changes, including a housing, main retainer, pilot valves, and auxiliary components to manage fluid flow and pressure differences during compression and rebound strokes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If damping force is reduced during rebound stroke in high-frequency region to improve ride comfort, then ride comfort is improved, but adjustment stability may deteriorate
Solution Approach 1:
The valve assembly is divided into multiple independent valves (first rebound valve, second rebound valve, compression valve) that independently control damping force at different frequencies. The first rebound valve handles high-frequency vibrations while the second rebound valve handles low-frequency vibrations, allowing separate optimization of ride comfort and adjustment stability without compromising either function
Solution Approach 2:
The damping force characteristics are made dynamic and frequency-dependent through the valve assembly design. Each valve responds differently based on the frequency of piston movement, automatically adjusting damping force to provide optimal performance across varying road conditions and vibration frequencies
2Reliability
If damping force is increased during compression stroke to improve adjustment stability, then adjustment stability is improved, but ride comfort may deteriorate
Solution Approach 1:
The damping control system is segmented into separate valves for compression and rebound strokes, with each stroke further divided by frequency. The compression valve handles compression damping while the dual rebound valves handle rebound damping at different frequencies, allowing independent optimization of stability and comfort for each function
Solution Approach 2:
Different damping force characteristics are applied locally to different frequency ranges and stroke directions. High-frequency rebound uses one damping characteristic for comfort, low-frequency rebound uses another for stability, and compression uses a third characteristic, creating locally optimized damping behavior throughout the system
3Reliability
If a single flow path piston valve is used to maintain constant damping characteristic at high speed, then adjustment stability is maintained, but ride comfort deteriorates due to inability to lower low speed damping force
Solution Approach 1:
The single flow path piston valve is replaced with a segmented valve assembly containing multiple independent valves (first rebound valve, second rebound valve, compression valve) with separate flow paths. This segmentation enables different damping characteristics for different speeds and frequencies, allowing low speed damping force to be reduced for comfort while maintaining high speed damping for stability
Solution Approach 2:
The valve assembly performs multiple functions that a single piston valve cannot achieve: it simultaneously provides high-speed damping for stability, low-speed damping reduction for comfort, high-frequency vibration damping, and low-frequency vibration damping. Each valve within the assembly handles a specific function, collectively providing universal damping control
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 design enhances ride comfort by reducing damping force during high-frequency vibrations while maintaining stability during low-frequency operations, preventing performance deterioration and improving assembly productivity through integrated manufacturing.
Implementation Method 1
a second pilot valve coupled to the piston rod and disposed above the pilot chamber and configure to be elastically deformable depending on a change in pressure of the pilot chamber
Implementation Method 2
the first pilot valve may be configured to be elastically deformable by pressure difference between the main chamber and the pilot chamber
Data Source
AI summary
Disclosed is a frequency sensitive type shock absorber including a piston rod reciprocating an inside of a cylinder and having a connection passage therein; a piston valve mounted on the piston rod and having a plurality of compression and rebound flow paths penetrating up and down thereof, and partitioning the cylinder into compression and rebound chambers; and a valve assembly mounted on the piston rod to generate a damping force that changes with frequency during a rebound stroke; wherein the valve assembly comprises a housing coupled to the piston rod and having a pilot chamber in communication with the connection passage; a main retainer coupled to the piston rod and having a main chamber formed on an upper portion thereof in communication with the connection passage; a first pilot valve coupled to the piston rod and disposed between the housing and the main retainer to partition the pilot chamber and the main chamber; and a second pilot valve coupled to the piston rod and disposed above the pilot chamber and configure to be elastically deformable depending on a change in pressure of the pilot chamber.