Active Valve Suspension Damping for Bottom-Out Control

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Solution Overview

Problem

Existing shock absorbers for vehicles face challenges with 'bottom out' conditions, where the dampening piston retracts due to compressive forces, leading to harsh rides and poor handling, and existing solutions do not provide a complete and adjustable system to account for dampening fluid temperature changes or allow for 'on-the-fly' adjustments.

Innovation Solution

A damper system with a fluid chamber divided by a piston into compression and rebound portions, featuring a bottom out cup and active valve that adjusts fluid flow rates based on vehicle acceleration data, allowing for dynamic adjustment of damping characteristics to prevent 'bottom out' and maintain optimal ride quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the dampening is increased to prevent bottom out, then the bottom out condition is avoided, but the ride becomes harsh and vehicle handling deteriorates

Engineering Contradiction:
Improvebottom out preventionVSAvoidride quality
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies dynamics by making the dampening characteristics adjustable through an active valve system. The valve can be remotely operated to change fluid flow rates through different orifices, allowing the dampening force to be dynamically adjusted based on operating conditions. This enables the system to provide high dampening when needed to prevent bottom out while maintaining softer dampening for normal ride quality.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes physical parameters by providing multiple orifices with different flow characteristics and using an active valve to selectively control fluid flow through these orifices. The valve can adjust the effective orifice size and flow rate, changing the dampening parameter from a fixed value to a variable one that can be optimized for different conditions such as temperature changes and terrain variations.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the dampening is set for high temperature operation, then bottom out is prevented at high temperatures, but the dampener is too stiff at low temperatures

Engineering Contradiction:
Improvebottom out prevention at high temperatureVSAvoidride quality at low temperature
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The active valve system enables dynamic adjustment of dampening characteristics to account for temperature variations. The valve can be remotely operated to increase fluid flow rates during initial low-temperature operation, providing softer dampening, and then adjusted to reduce flow rates when the fluid warms up, preventing bottom out at high temperatures.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the dampening parameter by providing multiple orifices with different flow characteristics and using the active valve to selectively control which orifices are active. This allows the effective dampening parameter to be changed based on temperature conditions, transitioning from a stiff setting for high-temperature operation to a softer setting for low-temperature operation.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the dampening is set to be soft initially, then ride quality is good, but bottom out occurs during extended use

Engineering Contradiction:
Improveride qualityVSAvoidbottom out prevention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The active valve system provides dynamic adjustment capability, allowing the dampening to start soft for good ride quality and then be increased during extended use to prevent bottom out. The remote operation capability enables the valve to be adjusted based on actual operating conditions and fluid temperature.

Inventive Principle:
Principle #15Dynamics

4Device complexity

If a fixed dampening system is used, then the system is simple, but it cannot adapt to temperature changes or terrain variations

Engineering Contradiction:
Improvesystem simplicityVSAvoidadaptability to temperature and terrain
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by replacing a fixed dampening system with one that has active control capability. The valve can be remotely operated to adjust fluid flow rates, enabling the system to adapt to different terrains and temperature conditions while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The active valve system provides multi-functionality by enabling the same dampener to perform both soft dampening for comfort and stiff dampening for bottom out prevention, as well as adapting to different temperature conditions. This eliminates the need for multiple fixed dampeners for different conditions.

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

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 system effectively prevents 'bottom out' by dynamically adjusting damping forces in response to vehicle conditions, ensuring a consistent ride quality regardless of temperature changes or terrain, thereby enhancing vehicle handling and comfort.

Implementation Method 1

an active valve coupled with said fluid flow path, said active valve to meter a fluid flow of a working fluid through said fluid flow path

Methodology Applied
Scientific EffectFluid flow metering:

Implementation Method 2

a damper chamber divided by a piston and shaft into a compression portion and a rebound portion

Methodology Applied
Scientific EffectHydraulic separation:

Implementation Method 3

a fluid flow path formed in the bottom out control feature for providing fluid communication from the bottom out control feature to the compression portion of the damper chamber during a compression stroke of the damper

Methodology Applied
Scientific EffectFluid communication:

Data Source

PatentEP3663605B1Position sensitive suspension damping with an active valve
Publication Date: 2023.06.07 FOX FACTORY INC
  • EP3663605B1 patent drawingFigure 1
  • EP3663605B1 patent drawingFigure 2
  • EP3663605B1 patent drawingFigure 3A

AI summary

A damper (200) for a shock absorber comprising: a damper chamber (220) divided by a piston (210) and shaft (215) into a compression portion and a rebound portion; a bottom out control feature (250, 275) at an end of the compression portion; a fluid flow path (302; 444) formed in the bottom out control feature for providing fluid communication from the bottom out control feature to the compression portion of the damper chamber during a compression stroke of the damper; and an active valve (350; 450, 450b) coupled with said fluid flow path, said active valve to meter a fluid flow of a working fluid through said fluid flow path.