Dual-Pressure Decoupling Piston for Constant Low-Pressure Actuation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing hydraulic decoupling devices in motor vehicles face challenges in maintaining consistent and high adjustment speed, especially at low pressure, due to fluctuations in spring force caused by mechanical spring tolerances and low activity speeds.

Innovation Solution

A decoupling device with a piston having two pressure chambers, where one chamber is loaded to move the piston in one direction and the other in the opposite direction, utilizing a radial arm and ball bearings for precise control, allowing for accurate and efficient decoupling and coupling operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a mechanical spring is used to reset the hydraulic cylinder, then the decoupling device can be reset to its original position, but the cylinder actuation speed becomes low and fluctuating, particularly at low pressure

Engineering Contradiction:
Improvecylinder actuation speedVSAvoidactuation speed consistency
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The piston is divided into two separate pressure chambers (first pressure chamber and second pressure chamber) that can be independently controlled. This segmentation allows each chamber to be pressurized independently to control the piston's movement in opposite directions, eliminating dependence on mechanical spring force and enabling consistent actuation speed even at low pressure

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If a single pressure chamber is used to actuate the piston, then the structure is simpler, but the piston cannot be precisely controlled in both directions with constant speed

Engineering Contradiction:
Improvepiston control precisionVSAvoidpressure chamber configuration
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The hydraulic actuator is segmented into two independently controllable pressure chambers, allowing precise control of piston movement in both directions through separate pressure applications, achieving high control precision while maintaining manageable structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the control parameter from single-pressure-source to dual-pressure-source, enabling independent control of piston extension and retraction speeds. This parameter change allows precise adjustment of actuation characteristics in both directions without mechanical spring interference

Inventive Principle:
Principle #35Parameter changes

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

Enables precise and consistent decoupling and coupling operations with improved control and reduced energy losses, enhancing the efficiency of 'sailing' mode in hybrid vehicles by maintaining high and constant adjustment speed even at low pressures.

Implementation Method 1

a first region of the piston is operatively connected to a first pressure chamber such that when pressure is applied to the first pressure chamber, the piston is displaced in a first direction

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

a second pressure chamber is present which is operatively connected to a second region of the piston such that when pressure is applied to the second pressure chamber, the piston is displaced in a second direction parallel to the longitudinal axis L, which is opposite to the first direction

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Data Source

PatentEP4281679B1Decoupling device and decoupling system
Publication Date: 2025.02.12 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP4281679B1 patent drawingFigure 1
  • EP4281679B1 patent drawingFigure 2
  • EP4281679B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a decoupling device (100) for separating a motor from a powertrain, having a piston (4) which is movably mounted in a housing (1) parallel to a longitudinal axis L of the housing (1) and which has an arm (6) for directly or indirectly actuating a coupling element (11). A first region (4a) of the piston (4) is operatively connected to a first pressure chamber (7) such that when pressure is applied to the first pressure chamber (7), the piston (4) is moved in a first direction parallel to the longitudinal axis L. The invention is characterized in that a second pressure chamber (8) is provided which is operatively connected to a second region (4b) of the piston (4) such that when pressure is applied to the second pressure chamber (8), the piston (4) is moved in a second direction parallel to the longitudinal axis L, said second direction being opposite the first direction.