Shock Absorber Valve Structure for Frequency-Adaptive Damping
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Solution Overview
Problem
Conventional shock absorbers have difficulty in simultaneously achieving ride comfort and steering stability due to their constant damping characteristics at varying speeds and frequencies, which are not adaptable to different road conditions.
Innovation Solution
A valve structure for shock absorbers that includes a main piston valve and a frequency unit, where the main piston valve generates damping forces based on piston speed and the frequency unit generates damping forces based on frequency, using a hollow housing, a free piston, and an auxiliary valve assembly to control fluid flow and damping forces across different amplitudes and frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single flow passage is used in the piston valve, then the structure is simple, but the damping force cannot be adjusted independently at different speeds
Solution Approach 1:
The piston valve is divided into multiple independent flow passages (first flow passage and second flow passage) that operate at different speed ranges. The first flow passage handles low-speed damping while the second flow passage handles high-speed damping, allowing independent adjustment of damping forces at different speeds without requiring a completely complex valve structure.
Solution Approach 2:
The valve structure incorporates movable components (such as the second piston and associated valves) that dynamically shift between different flow passages based on operating speed. This dynamic behavior enables the system to automatically select appropriate damping characteristics for different speed conditions, improving adaptability while maintaining structural efficiency.
2Adaptability or versatility
If damping force varies only with piston speed, then the valve structure is simple, but ride comfort and steering stability cannot be satisfied simultaneously
Solution Approach 1:
Different flow passages are designed with distinct damping characteristics tailored to specific operating conditions. The first flow passage is optimized for low-speed ride comfort with higher damping, while the second flow passage is optimized for high-speed steering stability with lower damping. This local optimization of damping properties allows simultaneous satisfaction of both ride comfort and steering stability requirements.
Solution Approach 2:
The system changes damping parameters (flow resistance, passage cross-section, valve opening areas) across different flow passages to achieve varying damping forces at different speeds. By adjusting these parameters independently in each flow passage, the system achieves adaptable damping characteristics that maintain reliable vehicle performance across diverse operating conditions.
3Ease of operation
If low-speed damping force is reduced to improve ride comfort, then ride comfort improves, but middle-speed and high-speed damping forces are also affected
Solution Approach 1:
The damping control is segmented into distinct speed ranges with dedicated flow passages. The first flow passage specifically addresses low-speed damping for ride comfort, while the second flow passage independently controls high-speed damping for steering stability. This segmentation allows reduction of low-speed damping force to improve ride comfort without adversely affecting middle-speed and high-speed damping forces, as each range is controlled separately.
Solution Approach 2:
The second piston acts as an intermediary mechanism that directs fluid flow between different passages based on speed conditions. It enables independent control of damping forces at different speeds by selectively opening or closing flow paths, allowing precise adjustment of low-speed damping for comfort without compromising high-speed 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
This solution allows for adaptable damping forces across various road conditions, enhancing both ride comfort and steering stability by varying damping characteristics according to speed and frequency, thereby improving vehicle performance.
Implementation Method 1
A flow of a working fluid pressurizing the free piston and a flow of a working fluid passing through the free piston and flowing to an opposite side of the free piston may be formed as a single flow
Data Source
AI summary
Provided is a valve structure of a shock absorber which is capable of controlling respective damping forces according to a frequency in compression and rebound motions of a piston valve, thereby satisfying both the ride comfort and the control stability. The valve structure of the shock absorber, which has a cylinder filled with a working fluid and a piston rod having one end located inside the cylinder and the other end extending outward from the cylinder, includes: a main piston valve assembly installed at one end of the piston rod and configured to operate in a state that the inside of the cylinder is divided into an upper chamber and a lower chamber, and generate a damping force varying according to a moving speed; and a frequency unit configured to move together with the main piston valve assembly and generate a damping force varying according to a frequency. The frequency unit includes: a hollow housing mounted at a lower end of the piston rod such that the housing is disposed under the main piston valve assembly; and a free piston disposed to be vertically movable within the housing.