Stem-Actuated Damper Valve for Soft Bottoming Control

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Solution Overview

Problem

Existing dampers lack control over damping effect near the end stroke, leading to inadequate soft bottoming performance.

Innovation Solution

A damper design featuring a stem assembly resiliently connected to the piston assembly and piston rod via a biasing means, with an elongated cavity that actuates a valve assembly to reduce damping medium flow as the piston nears the end member, enhancing compression resistance during end strokes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a valve with a movable element preloaded by a spring is provided in the end member to restrict flow when the piston nears the end stroke, then damping performance is improved, but control over the damping effect near the end stroke is lost

Engineering Contradiction:
Improvedamping performanceVSAvoidcontrol over damping effect
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The valve assembly is designed with a movable element that dynamically adjusts the flow restriction based on piston position. The movable element can shift between different positions to vary the degree of flow restriction, enabling controlled adjustment of damping characteristics during the end stroke phase rather than maintaining a fixed restriction level throughout.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The damping characteristics are modified by changing the flow restriction parameter through the movable valve element. By varying the opening degree of the valve orifice, the system can adjust the damping force applied to the piston, transitioning from high restriction to lower restriction as needed during the compression and rebound cycles.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If existing dampers lack control mechanisms for end stroke damping, then device complexity is reduced, but soft bottoming performance becomes inadequate

Engineering Contradiction:
Improvevalve control mechanismVSAvoidsoft bottoming performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The valve assembly incorporates a movable element that responds to piston motion to dynamically adjust flow restriction. This dynamic adjustment mechanism provides the necessary control for soft bottoming performance while maintaining reasonable structural complexity through the use of spring-loaded actuation and geometric relationships between components.

Inventive Principle:
Principle #15Dynamics

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 improved soft bottoming performance by controlling damping medium flow effectively, increasing compression resistance during end strokes and reducing manufacturing and assembly costs of progressive damping components.

Implementation Method 1

a stem assembly (112) resiliently connected to the piston assembly (111) and/or the piston rod (119) via a biasing means (117, 117')

Methodology Applied
Scientific EffectElastic potential energy storage and release: Spring

Implementation Method 2

a damper filled with a damping medium in use comprising... configured to control a damping medium flow entering or exiting the first working chamber (121)

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Data Source

PatentEP4311955A1damper
Publication Date: 2024.01.31 OHLINS RACING AB
  • EP4311955A1 patent drawingFigure 1
  • EP4311955A1 patent drawingFigure 2
  • EP4311955A1 patent drawingFigure 3

AI summary

Damper (100) filled with a damping medium in use comprising an inner tube (101); a movable assembly (110) comprising a piston assembly (111) and a piston rod (119) attached to said piston assembly (111), said movable assembly (110) being slidably disposed within the inner tube (101), the movable assembly (110) defining a first working chamber (121) and a second working chamber (122) within the inner tube (101), the piston rod (119) being disposed in the second working chamber (122); an end member (134) disposed at an end of the inner tube (101), the end member having an inner surface facing towards the first working chamber (121); an actuated valve assembly (137) being provided in the end member (134), said valve assembly (137) being configured to control a damping medium flow entering or exiting the first working chamber (121), wherein the movable assembly (110) comprises a stem assembly (112), said stem assembly being slidably connected to and partially embedded in said movable assembly (110).