Multistage Shock Absorber for Progressive Bottom-Out Damping

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Solution Overview

Problem

Standard shock absorbers are limited in their ability to effectively prevent bottoming out during severe driving conditions due to a lack of multiple stages of elevated damping force, leading to jarring impacts.

Innovation Solution

A multistage damping system with a primary, secondary, and tertiary piston assembly that progressively increases damping force as the shock absorber approaches bottoming out, utilizing a novel jounce control mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a standard shock absorber is used, then the structure is simple, but it bottoming out during severe driving conditions, producing jarring impacts

Engineering Contradiction:
Improveprevention of bottoming outVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The shock absorber is divided into multiple piston assemblies (primary, secondary, tertiary) that operate independently at different compression stages. Each piston assembly has its own damping characteristics, allowing the system to provide progressive resistance without requiring a completely complex redesign of the entire shock absorber structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a nested configuration where the secondary piston assembly is positioned within the primary piston assembly, and the tertiary piston assembly is positioned within the secondary piston assembly. This nested arrangement allows multiple damping stages to be integrated within a compact structure, preventing bottoming out while maintaining reasonable device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If a jounce control shock absorber with single stage elevated damping force is used, then bottoming out is partially prevented, but the system is limited in effectiveness due to providing only one stage of elevated damping force

Engineering Contradiction:
Improvebottoming out prevention effectivenessVSAvoiddamping force stages
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The shock absorber employs dynamic damping force adjustment through multiple piston assemblies that activate at different compression stages. The primary piston provides initial damping, the secondary piston engages at intermediate compression to provide elevated damping force, and the tertiary piston activates near bottoming out to provide a second stage of elevated damping force. This dynamic progression enhances adaptability to varying compression conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the damping force parameter progressively through different piston assemblies based on compression distance. Each piston assembly is designed with specific orifice configurations and spring characteristics that create distinct damping force levels, allowing the system to adapt to different driving conditions and provide appropriate resistance at each stage of compression.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If multiple piston assemblies are added to provide multistage damping force, then bottoming out prevention is improved, but the device complexity increases

Engineering Contradiction:
Improvebottoming out preventionVSAvoidpiston assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple piston assemblies into a single integrated shock absorber structure. The primary, secondary, and tertiary piston assemblies are combined within a common housing and damping medium system, allowing them to work together as a unified multistage damping system rather than separate components, thereby managing device complexity while maintaining bottoming out prevention effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

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 multistage damping system significantly reduces the likelihood of bottoming out by sequentially increasing damping force, providing enhanced vehicle stability and comfort during extreme driving conditions.

Implementation Method 1

an elongated housing containing a damping medium, an axially moveable primary piston assembly arranged in the housing

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Implementation Method 2

When the valve assembly engages the orifice, it regulates the flow of damping medium to provide a greater compressive damping force

Methodology Applied
Scientific EffectFluid flow regulation:

Implementation Method 3

A pressure spring is arranged between the bottom of the guide opening and the slide gate, which applies a spring force to the slide gate

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP3372865B1Multi-stage shock absorber
Publication Date: 2025.07.23 THYSSENKRUPP BILSTEIN OF AMERICA
  • EP3372865B1 patent drawingFigure 1
  • EP3372865B1 patent drawingFigure 2A
  • EP3372865B1 patent drawingFigure 2B

AI summary

Multistage damping system with an elongated housing containing a damping medium, an axially moveable primary piston assembly arranged in the housing comprising a primary piston and a valve assembly, an axially moveable secondary piston assembly, and an axially moveable tertiary piston assembly having a recessed cavity formed therein, wherein said secondary piston assembly is disposed within said recessed cavity. The axially moveable secondary piston may have an orifice disposed in a location to engage the valve assembly when the primary piston assembly is moved in a compressive direction beyond a particular compressive movement distance. When the valve assembly engages the orifice, it regulates the flow of damping medium to provide a greater compressive damping force when said primary piston assembly and said secondary piston assembly are moved beyond the particular compressive movement distance. The tertiary piston assembly is disposed and moveable within a second housing.The second housing is formed integral with the elongated housing.