Hydraulic Damper Sealing Ring Radial Expansion Control

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Solution Overview

Problem

Existing damper assemblies face issues with sealing ring misalignment and radial expansion, leading to hydraulic imbalance and potential failure due to the sealing ring being extruded into the space between the main tube and the additional piston assembly, which compromises the durability and reliability of the damper.

Innovation Solution

The damper assembly incorporates a sealing ring with annular collars that limit radial expansion and include a T-shaped cross-section with compression and rebound collars to form a locking engagement with the upper and lower members, preventing extrusion and enhancing stiffness, thereby minimizing hydraulic imbalance and misalignment effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the sealing ring is made radially expandable to compensate for misalignment, then the sealing performance and adaptability are improved, but the sealing ring becomes prone to extrusion into the space between the main tube and additional piston assembly

Engineering Contradiction:
Improvesealing ring adaptability to misalignmentVSAvoidsealing ring extrusion resistance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The sealing ring's radial dimension is made variable through controlled expansion during operation. The ring expands radially to compensate for misalignment between the additional piston assembly and main tube, while the expansion is limited by the engagement surfaces of the additional piston body, preventing excessive expansion that would cause extrusion.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The additional piston body is designed with engagement surfaces that preemptively limit the radial expansion of the sealing ring. This preliminary constraint prevents the sealing ring from expanding too much and being extruded into the gap between the main tube and additional piston assembly, counteracting the extrusion tendency before it occurs.

Inventive Principle:
Principle #9Preliminary anti-action

2Manufacturing precision

If the sealing ring is allowed to expand radially under working liquid pressure, then the sealing contact with the main tube is improved, but the sealing ring may be squeezed into the space between the narrowed section of the tube and additional piston assembly

Engineering Contradiction:
Improvesealing contact qualityVSAvoidsealing ring extrusion and squeezing
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The sealing ring utilizes controlled radial expansion under working liquid pressure to improve sealing contact with the main tube. The pressure-induced expansion enhances the sealing effect, while the additional piston body's engagement surfaces simultaneously constrain the expansion to prevent harmful extrusion.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The working liquid pressure that causes potential harmful extrusion of the sealing ring is converted into a beneficial force. The pressure drives the sealing ring to expand radially and engage firmly with the main tube, improving sealing contact. The additional piston body's engagement surfaces ensure this pressure-induced expansion remains controlled and beneficial rather than harmful.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Force

If the additional piston assembly is introduced into the narrowed section of the tube, then additional damping force is generated, but the sealing ring may misalign and be extruded due to dimensional and assembly misalignments

Engineering Contradiction:
Improveadditional damping forceVSAvoidsealing ring stability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The sealing ring's radial dimension is made dynamically adjustable through controlled expansion. This allows the ring to adapt to misalignments that occur when the additional piston assembly is installed in the narrowed section of the tube, maintaining reliable sealing contact despite dimensional variations and assembly misalignments.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The additional piston body incorporates engagement surfaces that preemptively limit the sealing ring's radial expansion. This preliminary constraint prevents the sealing ring from expanding excessively due to misalignment, thereby preventing extrusion into the gap between the main tube and additional piston assembly and maintaining reliability.

Inventive Principle:
Principle #9Preliminary anti-action

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 ensures robust, reliable, and cost-efficient damper performance with improved durability by restricting radial expansion of the sealing ring and maintaining fluid flow integrity even under pressure, reducing the risk of failure and enhancing manufacturing simplicity.

Implementation Method 1

the sealing ring being radially expandable in response to a working fluid pressure to engage the main tube during the compression stroke and the rebound stroke

Methodology Applied
Scientific EffectRadial expansion: Elasticity

Implementation Method 2

the sealing ring expanding radially under pressure of the working liquid

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Data Source

PatentEP3569891B1Hydraulic damper with a hydraulic stop arrangement
Publication Date: 2021.01.13 BEIJING WEST IND CO LTD
  • EP3569891B1 patent drawingFigure 1
  • EP3569891B1 patent drawingFigure 2
  • EP3569891B1 patent drawingFigure 3~5

AI summary

A damper assembly includes a main tube disposed on a center axis and defines a fluid chamber for containing a working fluid. A main piston is disposed in the fluid chamber dividing the fluid chamber into a rebound and a compression chamber. A piston rod is attached to the main piston for moving the main piston between a compression stroke and a rebound stroke. An additional piston is attached to the piston rod adjacent to the main piston. The additional piston includes a body having an upper and a lower member defining a groove. A sealing ring is disposed in the groove and being radially expandable in response to a working fluid pressure. The sealing ring includes at least one annular collar extending outwardly from the sealing ring for forming a locking engagement with the upper and lower members to limit the radial expansion of the sealing ring.