Bicycle Shock Absorber Control Using Magnetorheological Damping

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Solution Overview

Problem

Conventional shock absorbers for bicycles, particularly those using magnetorheological fluids, face challenges in providing flexible control and optimal damping responses under varying loads and terrain conditions, often requiring complex structures, high electrical energy consumption, and inefficient energy use.

Innovation Solution

A shock absorber system with a controllable damping valve and an electrical coil device that generates a field-sensitive medium, allowing real-time adjustment of damping force based on current relative speed, using a damper characteristic curve to dynamically set field strength and reduce energy consumption by only activating when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If magnetorheological fluids are used to adjust damping strength, then damping can be influenced by magnetic field, but a breakaway force must be overcome before fluid flows through the damping valve, causing delayed response

Engineering Contradiction:
Improvedamping adjustment capabilityVSAvoidresponse time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent replaces the purely mechanical breakaway force mechanism with an electrically controllable system. An electric motor actively rotates the damping valve body to adjust the magnetic field angle, eliminating the need for high breakaway forces and enabling immediate response to control signals without mechanical binding delays.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements continuous periodic rotation of the damping valve body via electric motor control. This periodic adjustment of the magnetic field angle allows the system to dynamically adapt damping characteristics in real-time, maintaining optimal performance without the limitations of static or manually adjusted systems.

Inventive Principle:
Principle #19Periodic action

2Adaptability or versatility

If separate, parallel damping chambers are used to adjust magnetic field strength, then damping can be regulated, but design complexity, assembly effort, and weight increase

Engineering Contradiction:
Improvedamping regulation capabilityVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the damping valve body with the magnetic field generation structure into a single integrated component. The valve body itself serves as the magnetic field carrier, eliminating the need for separate parallel damping chambers and external magnets, thereby reducing structural complexity while maintaining full damping regulation capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The damping valve body performs multiple functions simultaneously: it controls fluid flow direction and serves as the magnetic field generation structure. This multi-functional design eliminates the need for separate components for magnetic field generation, reducing overall device complexity and assembly requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If electrical coil device is used to generate magnetic field for damping control, then real-time adjustment is possible, but electrical energy consumption increases

Engineering Contradiction:
Improvereal-time control capabilityVSAvoidelectrical energy consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent uses periodic electric motor control to adjust the magnetic field angle only when damping adjustment is required, rather than maintaining continuous high energy consumption. The motor operates intermittently to rotate the valve body to new positions, then maintains those positions with minimal energy, significantly reducing overall electrical consumption while preserving real-time control capability.

Inventive Principle:
Principle #19Periodic 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

Enables flexible and energy-efficient damping control, providing a soft response under different loads and terrain conditions, with rapid reaction times and reduced electrical energy usage, allowing for optimal damping force adjustment in real-time.

Implementation Method 1

The damping device comprises at least one controllable damping valve with at least one field-generating device, in particular an electrical coil device with which a field-sensitive medium can be influenced in order to influence a damping force

Methodology Applied
Scientific EffectElectromagnetic field generation: Electromagnet

Implementation Method 2

Magnetorheological fluids typically consist of a suspension of small, magnetically polarizable particles finely dispersed in a carrier fluid such as oil. These polarizable particles, usually composed of carbonyl iron powder, typically have diameters between approximately 0.1 and 50 micrometers and, under the influence of a magnetic field, form chain-like structures capable of withstanding field-dependent shear stress.

Methodology Applied
Scientific EffectMagnetorheological effect: Magnetorheological Fluid

Data Source

PatentEP2679859B1Shock absorber and method for operating a shock absorber, in particular for a bicycle
Publication Date: 2023.05.24 DT SWISS AG
  • EP2679859B1 patent drawingFigure 1~2
  • EP2679859B1 patent drawingFigure 3
  • EP2679859B1 patent drawingFigure 4~5

AI summary

The method involves providing a damper device (1) with a controllable damping valve (8) having a field generating device (11). Parameter for current relative speed is periodically obtained between components (101, 102) in real time. Measure for field intensity to be currently set is derived by the parameter from characteristic damper curve in the real time. The field intensity to be currently set is generated in the real time with the field generating device for setting damping force in the real time that results from the characteristic damper curve at the parameter. An independent claim is also included for a shock absorber for a bicycle.