Shock Absorber Passage Area Adjustment for Variable Damping
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Solution Overview
Problem
Existing shock absorbers have limited design freedom in setting damping characteristics and reaction forces, making it difficult to achieve optimal performance in varying conditions.
Innovation Solution
A shock absorber design that includes a piston dividing the cylinder into two chambers, with a first passage and a second passage allowing fluid flow between them, and a damping valve, along with a passage area adjustment mechanism that adjusts the passage area based on the piston rod's position, allowing for varying damping forces depending on the stroke position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the spring force of the bias spring is increased to increase the damping force, then the damping force is improved, but the reaction force is increased and the degree of freedom in settings is reduced
Solution Approach 1:
The passage area adjustment mechanism dynamically changes the passage area of the second passage based on the piston rod position. This allows the damping force to vary dynamically throughout the stroke, enabling independent optimization of damping characteristics without being constrained by a fixed spring force setting. The mechanism transitions from a static spring-based system to a dynamic flow-area-controlled system.
Solution Approach 2:
The invention changes the parameter being controlled from spring force to passage area. By adjusting the passage area of the second passage according to piston rod position, the system achieves variable damping force without changing the spring force. This parameter substitution provides greater design freedom in setting damping characteristics.
2Power
If a bias spring is used to generate damping force, then the damping force is produced, but the reaction force from the spring limits design flexibility
Solution Approach 1:
The passage area adjustment mechanism acts as an intermediary between the piston movement and the damping force generation. Instead of relying directly on spring force, the system uses the passage area adjustment to control fluid flow and generate damping force. This intermediary mechanism decouples the damping force generation from the spring reaction force.
Solution Approach 2:
The invention uses hydraulic principles by controlling the flow of working fluid through passages with variable cross-sectional areas. The damping force is generated through fluid resistance in the controlled passages rather than mechanical spring force, providing smoother and more controllable damping characteristics.
3Reliability
If the damping force is increased to improve shock absorption, then the damping performance is improved, but the reaction force increases and affects ride comfort
Solution Approach 1:
The passage area adjustment mechanism creates different damping characteristics at different positions of the piston rod stroke. By locally adjusting the passage area according to position, the system provides high damping force when needed (for shock absorption) while maintaining lower damping force during normal operation (for ride comfort), achieving position-dependent optimization.
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 increases the degree of freedom in setting damping characteristics and reaction forces, improving ride comfort and damping performance by smoothly varying damping forces based on piston rod position, reducing the impact of shocks and enhancing vehicle stability.
Implementation Method 1
a damping valve installed at the first passage and configured to suppress a flow of the working fluid generated by movement of the piston and generate a damping force
Implementation Method 2
a passage area adjustment mechanism configured to adjust a passage area of the second passage depending on a position of the piston rod is installed
Data Source
AI summary
A shock absorber includes a first passage (111) or (112) and a second passage (32), (99) or (235) in communication with each other and configured to allow a working fluid to flow between two chambers (16) and (17) based on movement of a piston (15), and a passage area adjustment mechanism (101) or (236) configured to adjust a passage area of the second passage (99) or (235) depending on a position of a piston rod (18) is installed to have at least one of a maximum length-side property in which an extension-side damping force becomes soft and a compression-side damping force becomes hard in a range in which the piston rod (18) extends to an outside of a cylinder (11) farther than a maximum length-side predetermined position, and a minimum length-side property in which the extension-side damping force becomes hard and the compression-side damping force becomes soft in a range in which the piston rod (18) enters an inside of the cylinder (11) further than a minimum length side predetermined position.