Damper Sleeve Shock Absorber for Stable Damping Across Temperatures

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Solution Overview

Problem

Hydraulic shock absorbers in vehicles exhibit varying damping behavior under high loads and different temperature conditions, leading to inconsistent performance due to changes in fluid viscosity and material expansion, which affects ride comfort and driving dynamics.

Innovation Solution

The shock absorber design incorporates a damper sleeve with a smaller outer diameter than the cylinder and a piston with a larger inner diameter, forming an annular gap that expands elastically with increased piston speed, and uses materials with different thermal expansion coefficients to maintain consistent damping behavior across temperature ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydraulic shock absorbers are used to dampen vibrations, then ride comfort and driving dynamics are improved, but damping behavior becomes inconsistent under high loads and varying temperatures

Engineering Contradiction:
Improvedamping behavior consistencyVSAvoidperformance under varying conditions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the physical parameters of the system by introducing an annular gap between piston and damper sleeve that allows the effective damping area to vary with temperature and load conditions. This parameter change enables the shock absorber to maintain consistent damping behavior across different operating conditions by allowing thermal expansion and pressure-induced deformation to occur within the annular gap rather than causing performance degradation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The annular gap acts as an intermediary element between the piston and damper sleeve, providing a buffer zone that accommodates thermal expansion and pressure effects. This intermediary space allows the system to adapt to varying temperatures and loads while maintaining stable damping characteristics, effectively mediating between the conflicting requirements of consistency and adaptability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If piston speed increases to improve vibration damping, then damping force increases, but speed dependence of damping behavior increases

Engineering Contradiction:
Improvedamping forceVSAvoidpiston speed
Core Design Contradiction:
ForceVSSpeed

Solution Approach 1:

The patent introduces a dynamic element - the annular gap - that allows the damping characteristics to change with operating conditions. As piston speed increases, the annular gap allows for pressure equalization and reduces the speed-dependent variation in damping force, making the damping behavior more consistent across different speeds while still maintaining adequate damping force.

Inventive Principle:
Principle #15Dynamics

3Temperature

If materials with high thermal expansion are used, then temperature adaptation is improved, but dimensional stability under load decreases

Engineering Contradiction:
Improvetemperature range adaptationVSAvoiddimensional stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent explicitly utilizes thermal expansion by designing an annular gap between the piston and damper sleeve. This gap accommodates the thermal expansion of materials when temperature increases, preventing binding or seizure while maintaining proper clearance for hydraulic flow. The design allows controlled expansion without compromising dimensional stability during operation.

Inventive Principle:
Principle #37Thermal expansion

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 design ensures a substantially constant damping behavior, reducing speed dependence and maintaining uniform performance under varying loads and temperatures, enhancing ride comfort and driving dynamics.

Implementation Method 1

arranged in a cylinder (1) filled with a fluid (40), in which a damper sleeve (2) is arranged, through which a piston rod (3) is slidably guided, on which a piston (4) is arranged, whereby the outer diameter of the damper sleeve (2) is smaller than the inner diameter of the cylinder (1) and the inner diameter of the damper sleeve (2) is larger than the outer diameter of the piston (4), thereby forming an annular gap (43)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

uses materials with different thermal expansion coefficients to maintain consistent damping behavior across temperature ranges

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

Hydraulic shock absorbers in vehicles exhibit varying damping behavior under high loads and different temperature conditions, leading to inconsistent performance due to changes in fluid viscosity

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Data Source

PatentEP4461986A1Shock absorber
Publication Date: 2024.11.13 DRIVEMAN GMBH
  • EP4461986A1 patent drawingFigure 1a~2c
  • EP4461986A1 patent drawingFigure 3a~4c
  • EP4461986A1 patent drawingFigure 5a~6c

AI summary

The invention relates to a shock absorber comprising a cylinder (1) filled with a fluid and a piston rod (3) guided therein, wherein the piston rod (3) is guided into or through the cylinder (1) and is provided with at least one piston (4, 62), wherein at least one damper sleeve (2) is arranged in the cylinder (1) surrounding the at least one piston (4, 62), the outer diameter of which is smaller than the inner diameter of the cylinder (1) and the inner diameter of which is larger than the outer diameter of the at least one piston (4, 62), whereby an annular gap is formed between the at least one piston (4, 62) and the at least one damper sleeve (2) and a shell gap is formed between the at least one damper sleeve (2) and the cylinder (1), and wherein at least one of the at least one damper sleeve (2) is made of plastic.