Frequency-Sensitive Shock Absorber Valve for Adaptive Rebound Damping
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Solution Overview
Problem
Conventional shock absorbers struggle to simultaneously achieve ride comfort and adjustment stability due to their inability to effectively control damping force variations based on frequency and speed changes during compression and rebound strokes.
Innovation Solution
A frequency sensitive type shock absorber is designed with a valve assembly that adjusts damping force in response to changes in frequency and speed. This assembly includes a housing, a main retainer, and a pilot valve, which work together to control the flow of working fluid and generate damping forces that vary with frequency during the rebound stroke.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single flow path is used in the piston valve to maintain constant damping characteristic at high speed, then the medium and high speed damping force is maintained, but the low speed damping force cannot be reduced to improve ride comfort
Solution Approach 1:
The single flow path is divided into multiple flow paths: a first flow path for high-speed damping and a second flow path for low-speed damping. This segmentation allows independent control of damping characteristics at different speeds, resolving the contradiction between maintaining stable high-speed damping and reducing low-speed damping for comfort.
Solution Approach 2:
The valve structure transitions from a static single flow path to a dynamic multi-flow-path system where flow distribution changes based on operating conditions. The valve body and valve plug create different flow resistances dynamically responding to piston speed, enabling adaptive damping control across different speed ranges.
2Device complexity
If damping force changes only depending on speed change of the piston, then the structure is simple, but it generates the same damping force in various road surfaces making it difficult to satisfy both ride comfort and adjustment stability
Solution Approach 1:
Different regions of the valve system are assigned different damping characteristics. The first flow path is optimized for high-speed damping while the second flow path is optimized for low-speed damping. This local differentiation allows the system to provide appropriate damping for different road conditions without requiring a completely complex overall structure.
Solution Approach 2:
The system changes flow resistance parameters based on operating conditions by utilizing the geometric relationships between the valve body, valve plug, and flow paths. As piston speed and frequency change, the effective flow area and resistance change accordingly, providing adaptive damping without complex active control mechanisms.
3Ease of operation
If low speed damping force is reduced to improve ride comfort, then the medium and high speed damping force is affected when using a single flow path
Solution Approach 1:
The damping function is segmented into two independent flow paths: the first flow path handles medium and high speed damping while the second flow path handles low speed damping. This allows reduction of low-speed damping force for improved ride comfort without compromising the damping force at medium and high speeds.
Solution Approach 2:
The valve plug acts as an intermediary element that selectively opens or restricts different flow paths based on piston speed. At low speeds, it allows flow through the second flow path with reduced resistance for comfort, while at medium and high speeds, it directs flow through the first flow path maintaining stable damping force.
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 frequency sensitive type shock absorber effectively balances ride comfort and adjustment stability by generating damping forces that adapt to frequency and speed changes, thereby improving vehicle performance across various road conditions.
Implementation Method 1
a 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
Implementation Method 2
a damping device is equipped with a vehicle to improve ride comfort by absorbing shock or vibration applied from a road surface when driving
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 connecting passage; and a 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.