CSC Clutch Actuator Friction Locking for Bearing Drag Torque

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional clutch release systems face challenges in providing drag torque support in applications with limited installation space, often requiring complex assemblies and risk of slipping or damage due to increased drag torque, especially at low temperatures.

Innovation Solution

A release system that supports drag torque through friction within the Concentric Slave Cylinder (CSC) without using springs, featuring a first and second piston with radial expansions that create frictional contact with the housing to counteract drag torque, reducing the number of components and assembly complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If frictional locking devices are used to prevent rotation of the engagement bearing, then anti-rotation is achieved, but slipping occurs when drag torques increase at low temperatures

Engineering Contradiction:
Improveanti-rotation reliabilityVSAvoidslipping under increased drag torque
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical frictional locking device with a hydraulic locking mechanism. The hydraulic connection between the piston and engagement bearing creates a positive lock that prevents rotation regardless of drag torque magnitude, eliminating the slipping problem inherent in friction-based systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If positive locking devices are used to prevent rotation of the engagement bearing, then anti-rotation reliability is improved, but destruction of the anti-rotation device and damage to the actuating unit occurs

Engineering Contradiction:
Improveanti-rotation reliabilityVSAvoidresistance to destruction and damage
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The hydraulic fluid acts as an intermediary that transmits force uniformly between the piston and engagement bearing. This distributed force transmission prevents concentration of stress at single contact points, avoiding the destruction and damage problems associated with rigid positive locking devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If spring elements are used to support drag torque and provide anti-twist protection, then drag torque support is achieved, but the assembly becomes very complex

Engineering Contradiction:
Improvedrag torque supportVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into the piston-engagement bearing hydraulic connection. The same hydraulic link that provides actuation also supports drag torque and prevents twisting, eliminating the need for separate spring elements and reducing assembly complexity.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If conventional drag torque support solutions are used, then adequate drag torque support is provided, but installation space requirements increase

Engineering Contradiction:
Improvedrag torque supportVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The hydraulic connection serves multiple functions simultaneously: actuation force transmission, drag torque support, and anti-rotation locking. This multi-functionality eliminates the need for additional dedicated drag torque support components, reducing installation space requirements.

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

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 solution provides effective drag torque support with reduced space requirements, cost-effectiveness, and minimized noise and play, making it suitable for dual clutches in applications where no preload is necessary, while eliminating the risk of slipping and damage.

Implementation Method 1

the bearing drag torques of the first and/or second engagement bearing of the CSC also occur due to friction acting within the CSC

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2554868B2Clutch actuator
Publication Date: 2024.01.17 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP2554868B2 patent drawingFigure 1
  • EP2554868B2 patent drawingFigure 2~3

AI summary

The invention relates to a release system for actuating a clutch, the release system being designed in particular in the manner of a CSC (Concentric Slave Cylinder) and having at least one piston (2) which can be displaced in a housing (1) along a longitudinal axis (A) and whose in The end pointing in the direction of a pressure chamber (2.1) is provided with a seal (2.2) and the area opposite the seal acts on an engagement bearing (3), wherein, according to the invention, a bearing drag torque of the engagement bearing is supported by friction acting within the CSC.