Annular Piston Centering Ribs for Clutch Slave Cylinder Alignment

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Solution Overview

Problem

Existing central release devices for clutch systems experience wobbling due to component tolerances and lever arm tilting, leading to eccentric positioning of piston elements within pressure chambers, which increases load on sealing elements and causes sustained wear.

Innovation Solution

A central release device with a centering device, specifically ramp-shaped centering ribs on the piston element, ensures proper alignment and centering within the pressure chamber, reducing wobbling and eccentric positioning by adjusting diameter based on temperature states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional clutch devices are mounted on the engine side with lever arms, then clutch actuation is achieved, but component tolerances and lever arm tilting cause misalignment and wobble, leading to eccentric positioning of the piston element

Engineering Contradiction:
Improvealignment precisionVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The centering device is integrated directly into the piston element body, merging the centering function with the actuation function. This eliminates the need for separate centering mechanisms while achieving both precise alignment and effective clutch actuation through a unified structure

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The ramp-shaped centering ribs act as an intermediary mechanism between the piston element and pressure chamber wall. These ribs provide a mechanical interface that automatically centers the piston element during operation, mediating the alignment issue without requiring complex external positioning systems

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the piston element is allowed to wobble due to component tolerances, then manufacturing costs are reduced, but the sealing elements experience higher and continuous load, leading to increased wear

Engineering Contradiction:
Improvemanufacturing costVSAvoidsealing element durability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The centering device enables the piston element to self-center automatically during operation through the ramp-shaped ribs interacting with the pressure chamber wall. This self-adjusting mechanism compensates for manufacturing tolerances without requiring external intervention or complex active control systems

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The ramp-shaped centering ribs change their geometric relationship with the pressure chamber wall based on the piston element's position and orientation. As the piston moves or wobbles, the ramps convert radial deviations into axial forces that restore proper alignment, dynamically adjusting parameters to maintain optimal sealing contact

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the piston element is centered using a centering device, then eccentric positioning is prevented, but the device complexity increases

Engineering Contradiction:
Improvecentering precisionVSAvoidpiston element structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The centering function is segmented into discrete ramp-shaped ribs rather than requiring a continuous complex mechanism. These individual ribs can be integrated into the piston element structure as separate features, providing centering functionality through simple geometric elements rather than a elaborate assembly

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The ramp-shaped centering ribs utilize curved or inclined surfaces that naturally guide the piston element into proper alignment through geometric constraints. The curved geometry of the ramps provides automatic centering through contact mechanics, eliminating the need for straight edges or complex mechanical guides

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 centering device effectively maintains the piston element in a central position within the pressure chamber at operating temperatures, reducing wear on sealing elements and maintaining functionality by adjusting its centering properties according to temperature changes.

Implementation Method 1

adjusting diameter based on temperature states

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4010606B1Annular piston with a centering device for a concentric slave cylinder for hydraulically actuating a clutch and concentric slave cylinder
Publication Date: 2024.02.28 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP4010606B1 patent drawingFigure 1~2
  • EP4010606B1 patent drawingFigure 3~4

AI summary

The invention relates to a piston element (1) for a central release device (20) for engaging and releasing a clutch device, the piston element comprising: - a body (2) having a first portion (3) for sealing a pressure chamber (22) and having a second portion (4) for making contact with a release bearing device (24); the body (2) of the piston element (1) comprises a centring means (5) in order to centre the piston element (1) within a pressure chamber (22) of a housing element (21) of a central release device (20). The invention further relates to a central release device (20), in particular for a dual clutch, for a vehicle having a piston element (1) for a central release device (20) for engaging and releasing a clutch device.