Hydraulic Damper Compression Stop Assembly for Reduced Dead Length

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Solution Overview

Problem

Existing damper assemblies for vehicles have limitations in terms of dead length, performance, and cost efficiency, particularly in requiring substantial modifications to existing designs and lacking an effective compression stop mechanism.

Innovation Solution

The damper assembly incorporates a compression stop with an additional piston and a rod extender featuring orifices to enhance damping force, allowing fluid flow and increasing stroke length, which can be integrated as an add-on device without modifying existing components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a traditional damper assembly is used, then the structure is simple, but the dead length is excessive and performance is limited

Engineering Contradiction:
Improvedead lengthVSAvoidstructure complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The damper piston is segmented into a main piston and an additional piston, with the additional piston having a smaller diameter than the main piston. This segmentation allows the additional piston to fit within the fluid chamber alongside the main piston, enabling reduced dead length without requiring complete structural redesign of the damper assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The additional piston with smaller diameter is nested within the fluid chamber in a configuration that allows it to move independently while occupying space efficiently. This nested arrangement enables the compression stop mechanism to function within the existing damper geometry, reducing dead length without proportionally increasing overall device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If existing damper designs are modified to improve performance, then performance improves, but substantial modifications are required increasing cost and complexity

Engineering Contradiction:
Improvedamping performanceVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The additional piston serves multiple functions: it acts as a compression stop, provides additional damping during compression strokes, and maintains fluid sealing. This multi-functionality allows a single component to deliver multiple performance benefits without requiring separate mechanisms, thereby improving damping performance without proportionally increasing manufacturing complexity or cost.

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

3Force

If compression stop mechanism is added to increase damping force, then damping performance improves, but device complexity increases

Engineering Contradiction:
Improvedamping forceVSAvoidmechanism complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The compression stop function is merged with the additional piston, which is already present in the fluid chamber. By combining the compression stop role with the additional piston structure, the design achieves enhanced damping force without adding a completely separate compression stop mechanism, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The compression stop mechanism utilizes hydraulic pressure from the working fluid to generate the additional damping force. During compression strokes, the additional piston experiences fluid pressure that creates a reactive force against the compression direction. This hydraulic approach generates increased damping force without requiring complex mechanical spring or friction-based compression stop mechanisms.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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

This configuration reduces dead length, improves performance, and is cost-efficient, providing an effective damping mechanism that can be easily integrated into existing damper designs, enhancing both compression and rebound strokes.

Implementation Method 1

The additional piston is slidably disposed in the compartment and movable between a first position in response to the compression stroke and a second position in response to the rebound stroke to increase stroke length of the compression stroke and the rebound stroke

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

The rod extender defines at least one orifice for allowing the working fluid to flow into said compartment, wherein said at least one orifice includes a plurality of orifices disposed along said rod extender radially and axially spaced from one another

Methodology Applied
Scientific EffectFluid flow through orifices: Pressure Drop

Data Source

PatentEP3578848B1Hydraulic damper with a compression stop assembly
Publication Date: 2023.11.15 BEIJING WEST IND CO LTD
  • EP3578848B1 patent drawingFigure 1
  • EP3578848B1 patent drawingFigure 2
  • EP3578848B1 patent drawingFigure 3a~3b

AI summary

A damper assembly includes a main tube disposed on a center axis and extending between a first and a second end defining a fluid chamber for containing a working fluid. A main piston is slidably disposed in the fluid chamber dividing the fluid chamber into a rebound chamber and a compression chamber. A piston rod is attached to the main piston for moving the main piston between a compression and a rebound stroke. The piston rod includes a rod extender attached to the main piston defining a compartment. A compression stop includes an additional piston is slidably disposed in the compartment and movable between a first position in response to the compression stroke and a second position in response to the rebound stroke. The first position is the additional piston being disposed adjacent the main piston. The second position is the additional piston being axially spaced from the main piston.