Compression Damper Shim Stack for Multi-Speed Damping Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing vehicle suspension systems require multiple fluid circuits to manage varying compression speeds, which increases weight and manufacturing costs while reducing performance.

Innovation Solution

A damper with a recirculation system using a single type of oil, featuring a compression damper with a single adjustable fluid circuit and a positionally adjustable floating shim stack to control damping rates across multiple compression speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple fluid circuits are used to accommodate varying compression speeds, then the damping function capability is improved, but the weight of the shock absorber increases

Engineering Contradiction:
Improvedamping function capabilityVSAvoidweight of shock absorber
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent merges multiple separate fluid circuits into a single integrated fluid circuit that handles both high-speed and low-speed compression functions. The circuit includes a first fluid passageway with a shim stack for high-speed compression and a second fluid passageway with a second shim stack for low-speed compression, both within one continuous circuit. This consolidation reduces the number of separate components and overall weight while maintaining the capability to provide appropriate damping for varying compression speeds.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple fluid circuits are used to accommodate varying compression speeds, then the damping function capability is improved, but the device complexity increases

Engineering Contradiction:
Improvedamping function capabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent consolidates multiple fluid circuits into one integrated circuit with multiple passageways that share common elements. The single circuit design with interconnected passageways, shared reservoir space, and common piston structure reduces the number of separate components, seals, and mounting points required, thereby reducing device complexity while maintaining multi-speed compression capability through the use of adjustable shim stacks.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single fluid circuit is designed to perform multiple functions by incorporating different passageways for high-speed and low-speed compression within the same circuit. The circuit can selectively engage different damping mechanisms based on compression speed, providing universal functionality across varying operational conditions without requiring separate dedicated circuits for each function.

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

3Reliability

If the diameter of the shock absorber is increased to enhance damping capability, then the damping function is improved, but the weight of the shock absorber increases

Engineering Contradiction:
Improvedamping capabilityVSAvoidweight of shock absorber
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies local quality by creating regions of different damping characteristics within the single fluid circuit. The first fluid passageway with its shim stack provides localized high-speed compression damping, while the second fluid passageway with its second shim stack provides localized low-speed compression damping. This allows the shock absorber to provide enhanced damping capability across different operating conditions without requiring a uniformly larger diameter throughout the entire structure.

Inventive Principle:
Principle #3Local quality

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 allows for adjustable damping rates across a range of compression speeds using a single fluid circuit, reducing weight and manufacturing costs while enhancing performance compared to conventional systems.

Implementation Method 1

upon compression, enabling oil to leak from said fluid filled chamber of said compression damper to a position exterior to said fluid filled chamber

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Gradient

Implementation Method 2

said recirculation system comprising: a cartridge comprising a compression damper of a shock absorber

Methodology Applied
Scientific EffectFluid recirculation: Convection

Implementation Method 3

a positionally adjustable floating shim stack positioned at one end of said fluid passageway, said positionally adjustable floating shim stack configured for selectively blocking a flow of fluid through said fluid passageway

Methodology Applied
Scientific EffectMechanical blocking: Valve

Implementation Method 4

said recess comprises a curvature at one side configured for guiding said oil toward a wall of an air chamber of said compression damper

Methodology Applied
Scientific EffectFluid guidance: Flow Separation

Data Source

PatentEP3109502B1Compression piston
Publication Date: 2025.05.07 FOX FACTORY INC
  • EP3109502B1 patent drawingFigure 1A
  • EP3109502B1 patent drawingFigure 1B
  • EP3109502B1 patent drawingFigure 1C

AI summary

A compression damper (104) of a shock absorber includes: a single adjustable fluid circuit configured for controlling a damping rate associated with multiple compression speeds of the shock absorber, wherein the single adjustable fluid circuit includes a fluid passageway (322) through a base valve (112); and a positionally adjustable floating shim stack positioned at one end of the fluid passageway, the positionally adjustable floating shim stack (218) configured for selectively blocking a flow of fluid through the fluid passageway (322).