Hydraulic Damper Stroke Stop Ring Guide Locking

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Solution Overview

Problem

Existing hydraulic damper stop arrangements fail to maintain a secure lock during high-speed movements, leading to potential unlocking and reduced operational length due to high pressure and misalignment of components, which affects the damping force and stroke length.

Innovation Solution

The ring guide is secured with self-locking assembly clips and a design where the fixing protrusions' height exceeds the radial clearance, ensuring engagement in an annular groove of the piston rod, and the ring guide is positioned with radial channels and a plastic narrowed section to enhance holding and prevent blocking, allowing for increased stroke length and damping force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixing protrusion is used to secure the ring guide to the piston rod, then the ring guide can be locked in position, but during high-speed movement the pressure acting on the ring may cause unlocking of the ring guide from the piston rod

Engineering Contradiction:
Improvelocking reliabilityVSAvoidresistance to high pressure
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The fixing mechanism is segmented into multiple fixing protrusions distributed around the ring guide, rather than a single fixing point. This distributes the pressure load across multiple engagement points, preventing localized failure and maintaining locking reliability under high-speed pressure conditions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fixing protrusions are integrated directly into the ring guide structure itself, merging the guiding function and the fixing function into a single unified component. This eliminates separate locking mechanisms and creates a more robust integrated solution that maintains strength under pressure

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If the axial length of the retaining surface is increased to ensure proper snap-locking of the ring guide, then the locking is more secure, but the operational length of the hydraulic stop arrangement is reduced

Engineering Contradiction:
Improvesnap-locking securityVSAvoidoperational length
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The fixing mechanism transitions from relying on axial length of the retaining surface to using radial protrusions that engage with the piston rod. This dimensional shift allows secure locking without consuming axial space, thereby preserving the operational length of the hydraulic stop arrangement

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of operation

If the ring guide and ring form a return valve that opens during high-speed movement, then the valve functions as intended, but the high pressure may push the bridge stuck inside the annular gap causing failure

Engineering Contradiction:
Improvevalve operationVSAvoidfailure prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The design incorporates a safety margin where the fixing protrusions engage the piston rod at a position that prevents the bridge from being pushed into the annular gap in the first place. This preemptive positioning cushions against the high-pressure forces that would otherwise cause the bridge to stick and fail

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 solution provides a reliable and cost-efficient hydraulic damper with improved holding function, increased stroke distance, and smooth damping force increase at the end of the stroke, preventing the ring guide from entering and blocking the sealing ring, thus enhancing the overall performance and durability.

Implementation Method 1

a tube filled with working liquid, a main piston assembly disposed slidably inside the tube along an axis, dividing the tube into a rebound chamber and a compression chamber and provided with rebound and compression valve assemblies to control the flow of working liquid within the tube

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

Hydraulic suspension damper with a hydraulic stroke stop arrangement

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Implementation Method 3

an additional piston assembly having a diameter smaller than the diameter of the tube, displaceable along with the main piston assembly configured to be slidably disposed in the narrowed section to generate additional damping force

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4027036A1Hydraulic suspension damper with a hydraulic stroke stop arrangement
Publication Date: 2022.07.13 BEIJING WEST IND CO LTD
  • EP4027036A1 patent drawingFigure 1
  • EP4027036A1 patent drawingFigure 2
  • EP4027036A1 patent drawingFigure 3~5b

AI summary

The disclosure relates to a hydraulic damper provided with an additional stroke stop arrangement comprising a narrowed section and an additional piston assembly, wherein the additional piston assembly comprises a plastic ring guide, a ring, and a retaining member, wherein the ring surrounds an inner axial rim of the ring guide with radial clearance, wherein the inner axial rim defines at least one annular channel, and wherein the ring guide has at least one fixing protrusion extending radially inwardly toward the axis for engaging an annular slot in the piston rod and securing the ring guide to the piston rod. The at least one fixing protrusion is disposed at said inner axial rim of said ring guide and the height of said at least one fixing protrusion is larger than said radial clearance between said inner axial rim of said ring guide and said ring.