Shock Absorber Damping Control via Piston Rod Position
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Solution Overview
Problem
Current shock absorbers require further improvement in damping force properties to enhance vehicle performance and ride comfort.
Innovation Solution
A shock absorber design featuring a cylinder with a piston and a communication passage that includes a damping force generating device, which adjusts the damping coefficient based on the piston rod's position, providing varying damping states and coefficients to optimize damping force characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional displacement response type shock absorber is used, then the basic damping force function is provided, but the damping force properties require further improvement
Solution Approach 1:
The damping force generating device dynamically adjusts the damping coefficient based on piston rod position. The device transitions from a static damping system to a dynamic one where the damping coefficient varies continuously according to the piston rod's position, achieving improved damping force properties without requiring multiple discrete components
Solution Approach 2:
The invention changes the damping coefficient parameter as a function of piston rod position. By establishing a relationship where the damping coefficient varies with position, the system achieves optimized damping characteristics across different stroke ranges, resolving the contradiction between basic function and improved properties
2Ease of operation
If the damping coefficient is kept constant, then the device structure is simple, but the damping force variation is insufficient for optimal ride comfort
Solution Approach 1:
The damping force generating device automatically adjusts the damping coefficient based on the piston rod position without requiring external control systems. The device uses the mechanical position of the piston rod itself as the control input, creating a self-regulating system that improves ride comfort while maintaining structural simplicity
Solution Approach 2:
The system incorporates position-dependent feedback where the piston rod position directly influences the damping coefficient. This feedback mechanism ensures that the damping force adapts to the current state of the shock absorber, optimizing ride comfort through automatic adjustment rather than complex external 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
The design improves damping force characteristics, allowing for smoother damping force variation and enhanced ride comfort by adjusting the damping coefficient in response to piston rod position, effectively addressing the limitations of existing shock absorbers.
Implementation Method 1
a damping force generating device installed at the communication passage and configured to limit a flow of the working fluid generated by movement of the piston to generate a damping force
Implementation Method 2
a bias spring configured to bias a disc valve to generate a damping force, configured to vary a spring force of the bias spring according to a position of a piston with respect to a cylinder
Data Source
AI summary
A minimum length-side property in which an extension-side damping coefficient signifies a hard state in a range (Aa0) where the piston rod enters further inside the cylinder than a minimum length-side predetermined position (Sa1), and a maximum length-side property in which the extension-side damping coefficient signifies a soft state in a range (Aa4) where the piston rod extends further outside the cylinder than a maximum length-side predetermined position (Sa4) are included. An extension-side damping force property between the minimum length-side predetermined position (Sa1) and the maximum length-side predetermined position (Sa4) includes a part (Sa1 to Sa2, Sa3 to Sa4) in which a damping coefficient change rate with respect to a stroke of the piston rod is large and a part (Sa2 to Sa3) in which the damping coefficient change rate is small. At least when the piston rod strokes to the extension side from the minimum length-side predetermined position (Sa1), the damping coefficient change rate is allowed to be large.