Hydraulic Damper Sealing Ring for Controlled Damping Force
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Solution Overview
Problem
Existing hydraulic dampers with hydraulic stop arrangements generate excessive damping forces, leading to high loads on damper and structural vehicle components, due to progressive characteristics of additional damping force across the entire operating range.
Innovation Solution
A hydraulic damper design featuring a secondary piston assembly with axial and annular projections, a spring seat, and a sealing ring that activates additional flow channels at a tunable pressure threshold, allowing for controlled increase in damping force based on piston position and velocity, and includes annular seats to reduce spring stiffness and axial slots for smooth pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a hydraulic stop arrangement with progressive damping force is used, then damping force increases progressively based on rod displacement, but excessive damping forces are generated that may damage damper and vehicle components
Solution Approach 1:
The patent applies parameter changes by introducing a sealing ring that moves between two positions to change the flow characteristics. In the first position, the sealing ring connects the annular channel with axial slots allowing free flow. In the second position, it connects with radial slots creating a restricted flow path. This changes the damping parameter from progressive to limited, resolving the contradiction between achieving progressive damping and preventing excessive forces.
Solution Approach 2:
The patent implements dynamics through the movable sealing ring that transitions between two operational states based on pressure differential. The sealing ring dynamically switches the flow path configuration, enabling the system to adapt between progressive damping (first position) and force limitation (second position), thus resolving the static contradiction in damping characteristics.
2Force
If a compression valve assembly is added to make damping force dependent on rod speed, then the additional damping force becomes dependent on both position and speed, but the construction becomes more complex
Solution Approach 1:
The patent applies universality by making the sealing ring perform multiple functions: it acts as a sealing element, a flow path selector, and a pressure-actuated valve. Instead of adding a separate compression valve assembly, the sealing ring itself controls both position-dependent and speed-dependent damping characteristics, reducing construction complexity while maintaining force control.
Solution Approach 2:
The patent merges the functions of the sealing element and the flow control valve into a single component - the sealing ring. This consolidation eliminates the need for separate compression valve assemblies, reducing part count and construction complexity while achieving both position and velocity dependence in damping force control.
3Stability of the object's composition
If axial slots are provided in the annular projection, then smooth pressure distribution is achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies self-service through the pressure differential acting on the sealing ring, which automatically positions itself to connect with either axial or radial slots based on the operating conditions. The system self-regulates the flow path without requiring external control mechanisms, achieving smooth pressure distribution while reducing the need for high manufacturing precision in slot alignment.
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 provides a controlled and progressive increase in damping force, limiting excessive loads on components by allowing adjustable tuning of damping force gains for both compression and rebound strokes, effectively managing piston position and velocity-dependent performance.
Implementation Method 1
The sealing ring is axially movable between a first position and a second position, wherein said sealing ring engages the annular projection in the first position to fluidly connect the annular channel with the axial slots of the annular projection, and wherein the sealing ring engages the retaining member in the second position
Implementation Method 2
A spring engages the spring seat and preloads the spring seat in a direction opposite the main piston assembly
Implementation Method 3
a tube extending along an axis and defining a chamber for holding a fluid
Implementation Method 4
a hydraulic damper for a vehicle including a main piston assembly and a secondary piston assembly
Data Source
Figure 1~2
Figure 3a~4b
Figure 5a~6c
AI summary
The invention relates to a hydraulic damper for a motor vehicle comprising: a tube extending along an axis and defining a chamber for holding a fluid; said tube having a main section having a first diameter and a narrowed section having a second diameter being smaller than said first diameter; a main piston assembly slidably disposed inside said main section of said tube; a main piston rod attached to said main piston assembly and extending axially outside of said tube; a secondary rod coupled with and extending axially from said main piston rod; a spring seat disposed about said secondary rod and axially moveable relative to said secondary rod; a spring engaging said spring seat and preloading said spring seat in a direction opposite said main piston assembly; a secondary piston disposed about and coupled with said secondary rod; said secondary piston having an axial projection and an annular projection, wherein said axial projection extends axially and wherein said annular projection extends radially outwardly relative to said axial projection and abuts said spring seat and defines a plurality of axial slots extending axially therethrough; a retaining member coupled with said secondary rod on the axially opposite side of said secondary piston as said spring seat and having an outer face defining a plurality of spaced radial slots extending radially inwardly into radial alignment with said axial slots of said secondary piston; a sealing ring having an external diameter substantially corresponding to the second diameter and disposed about said axial projection axially between said annular projection and said retaining member and axially moveable relative to said axial projection; an annular channel defined radially between said sealing ring and said axial projection; and said sealing ring being axially moveable between a first position and a second position, wherein said sealing ring engages said annular projection in said first position to fluidly connect said annular channel with said axial slots of said annular projection, and wherein said sealing ring engages said retaining member in said second position to fluidly connect said annular channel with said radial slots of said retaining member.