Dual-Piston Shock Absorber With Pressure Equalization

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Solution Overview

Problem

Existing hydraulic shock absorbers exhibit inconsistent damping behavior under high loads due to increased fluid temperature causing pressure changes within the cylinder.

Innovation Solution

Incorporation of pressure equalization elements, such as elastomeric foam or sponge rubber, which expand or contract in response to fluid pressure changes to maintain consistent damping characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If hydraulic oil is used for damping vibrations, then damping force increases with compression or rebound speed, but fluid temperature increases under high loads causing pressure changes and inconsistent damping behavior

Engineering Contradiction:
Improvedamping forceVSAvoidfluid temperature
Core Design Contradiction:
ForceVSTemperature

Solution Approach 1:

The patent introduces a pressure equalization element that changes its volume in response to pressure changes caused by temperature increases. This allows the system to compensate for thermal expansion of the hydraulic oil by adjusting the available volume, thereby maintaining consistent damping behavior despite temperature variations during high-load operation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The pressure equalization element acts as an intermediary between the hydraulic oil and the piston system. It absorbs the effects of thermal expansion and pressure changes, preventing these from directly affecting the damping force generation, thus decoupling the temperature effect from the damping performance

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If pressure equalization elements are added to compensate for temperature-induced pressure changes, then damping consistency improves, but device complexity increases

Engineering Contradiction:
Improvedamping consistencyVSAvoidshock absorber structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a porous pressure equalization element that allows hydraulic oil to penetrate and compress within its structure. This porous design enables volume compensation for thermal expansion while maintaining a relatively simple structural form that integrates smoothly into the existing shock absorber architecture, minimizing the increase in device complexity

Inventive Principle:
Principle #31Porous materials

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 pressure equalization elements stabilize fluid pressure, ensuring consistent damping performance by compensating for temperature-induced pressure fluctuations, thereby maintaining stable damper performance.

Implementation Method 1

changes in damping behavior can occur under high loads... a high load causes an increase in the fluid temperature inside the cylinder. Due to the incompressibility of the fluid, in this case a hydraulic oil, this results in a pressure increase within the cylinder

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

at least one pressure equalization element in the cylinder, which has a pressure-dependent variable volume and is in contact with the fluid, counteracts this pressure increase within the cylinder... When the pressure increases, the pressure equalization element is compressed, releasing additional volume within the cylinder and thus equalizing the pressure

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4506587B1Shock absorber
Publication Date: 2026.02.25 DRIVEMAN GMBH
  • EP4506587B1 patent drawingFigure 1a~1c
  • EP4506587B1 patent drawingFigure 2
  • EP4506587B1 patent drawingFigure 3a~3c

AI summary

The invention relates to a shock absorber comprising a cylinder (1, 6) filled with a fluid and a piston rod (3, 7) guided therein, wherein the piston rod (3) is guided into or through the cylinder (1, 6) and is provided with two pistons (41, 73, 76) spaced apart from each other, in which axial bores (42, 74) are provided circumferentially radially spaced from the piston rod (3, 7) and on the outside of each of which a sealing disc (43, 75) for closing the axial bores (42, 74) of the associated piston (41, 73, 76) is axially movably mounted on the piston rod (3, 7), wherein the inner wall of the cylinder encompassing the pistons (41, 73, 76) has at least in certain regions a diameter that changes continuously in the axial direction, wherein at least one pressure equalization element (5, 5', 5", 5‴) is arranged, which has a pressure-dependent variable volume and is in contact with the fluid.