Shock Absorber Damping Force Control via Jet Stream Redirection
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Solution Overview
Problem
Existing shock absorbers face a narrow adjustment range of damping force in the medium-high speed region, leading to either excessive damping or insufficient control.
Innovation Solution
A shock absorber design incorporating a damping force generating apparatus with a main flow path, a bypass flow path, a pilot chamber, and a pilot flow path, where a jet stream generated in the main flow path joins the flow from the pilot chamber, allowing for adjustment of back pressure and damping force by controlling the flow direction and interaction between the jet stream and pilot stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the flow path area of the variable orifice is decreased to increase damping force, then the damping force is adjusted to a hard side, but the opening degree of the disc valve decreases and the gap between the disc valve and valve seat decreases, causing the working fluid to become a jet stream which generates excessive damping force in the medium-high speed region
Solution Approach 1:
The patent introduces a guide portion as an intermediary element that redirects the jet stream of working fluid away from the gap between the disc valve and valve seat. The guide portion changes the flow direction of the jet stream to eject it along the outer circumferential portion of the valve seat toward a gap between the valve seat and guide portion, thereby preventing the jet stream from directly acting on the disc valve and reducing excessive damping force in the medium-high speed region
Solution Approach 2:
The patent modifies the flow characteristics by changing the direction of the jet stream through the guide portion. By altering the ejection angle and flow path of the working fluid, the system changes how the jet stream interacts with the valve components, thereby adjusting the damping force characteristics in the medium-high speed region without changing the orifice area
2Object-affected harmful factors
If a guide portion is formed to redirect the jet stream, then excessive damping force in the medium-high speed region is prevented, but the adjustment range of damping force becomes relatively narrow
Solution Approach 1:
The patent segments the flow control into multiple independent pathways: the main flow path through the disc valve, the bypass flow path, and the pilot flow path through the variable orifice. This segmentation allows each pathway to be adjusted independently, enabling broader damping force adjustment range while the guide portion manages the jet stream direction to prevent excessive damping in specific speed regions
Solution Approach 2:
The patent employs a variable orifice whose opening area can be dynamically adjusted, and a disc valve that opens and closes based on pressure conditions. This dynamic control mechanism, combined with the guide portion, allows the system to adaptively manage damping force across different speed regions, expanding the overall adjustment range while preventing excessive damping where needed
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 enables a wider adjustment range of damping force in the medium-high speed region, allowing for precise control of damping characteristics by manipulating the back pressure and flow interactions, thereby optimizing damping performance.
Implementation Method 1
a pilot chamber into which the working fluid flows via the bypass flow path and which applies an internal pressure in a valve closing direction to the main valve by a pressure of the working fluid
Implementation Method 2
a jet stream which is generated in a flow path narrowed by the main valve in the main flow path joins the flow of the working fluid which flows out from the pilot chamber via the pilot flow path
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A damping force generating apparatus (20) of a shock absorber (1) includes a main flow path (70, 80) through which a working fluid flows, a main valve (30) which generates a damping force by controlling the flow of the working fluid by opening and closing the main flow path (70, 80), a pilot chamber (31) into which the working fluid branched from the main flow path (70, 80) flows and which applies an internal pressure in a valve closing direction to the main valve (30) by a pressure of the working fluid, and a pilot flow path (90) to which the working fluid flows out from the pilot chamber (31). In addition, a jet stream which is generated in a flow path narrowed by the main valve (30) in the main flow path joins the flow of the working fluid which flows out from the pilot chamber (31) via the pilot flow path (90).