Friction Clutch Leaf Spring Layout for Overtravel Control

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Solution Overview

Problem

Existing friction clutches for motor vehicle drive trains require additional components like wire rings to introduce supporting forces, which increases complexity and potentially adverse effects during actuation.

Innovation Solution

A friction clutch design that uses leaf springs with a dual section structure, where the first section provides a partial supporting force and the second section counteracts further displacement, eliminating the need for additional components like wire rings and ensuring stable operation by limiting overtravel and maintaining frictional engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wire rings are used to introduce supporting force into the plate spring, then the plate spring can be supported in both actuated and unactuated states, but the number of components increases and device complexity increases

Engineering Contradiction:
Improvesupporting force functionVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the centering function and supporting force function into a single component - the leaf spring. The leaf spring is riveted to the clutch cover and provides both centering of the plate spring and supporting force through its rigid second section, eliminating the need for separate wire rings and reducing component count while maintaining reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The leaf spring serves multiple functions simultaneously: it connects the pressure plate to the clutch cover, provides rotational fixation, enables limited axial displacement, centers the plate spring, and introduces supporting force. This multi-functionality reduces the overall number of components needed in the friction clutch system

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

2Ease of operation

If the plate spring is allowed to travel freely during actuation, then the clutch can be fully disengaged, but overtravel may cause unintended clutch closure or damage

Engineering Contradiction:
Improveactuation rangeVSAvoidovertravel control
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The rigid second section of the leaf spring is positioned to contact the plate spring before full actuation occurs. This preliminary contact establishes a stop that prevents overtravel before it can cause damage or unintended closure, while still allowing the necessary full actuation range for proper clutch disengagement

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If additional components like wire rings are added to improve supporting force, then the plate spring stability improves, but manufacturing complexity and assembly difficulty increase

Engineering Contradiction:
Improveplate spring stabilityVSAvoidassembly complexity
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

By merging the centering bolt and wire ring functions into the single leaf spring component, the patent simplifies manufacturing and assembly. The leaf spring is riveted directly to the clutch cover in one operation, eliminating the need for separate riveting operations for centering bolts and installation of wire rings, thereby reducing assembly complexity while maintaining plate spring stability

Inventive Principle:
Principle #5Merging (Combining)

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 dual-section leaf spring design reduces the number of components required, enhances the supporting force, and prevents unintended clutch closure by distributing the force effectively, ensuring reliable operation and reduced complexity.

Implementation Method 1

The plate spring (8) acts with a force edge (11) on the pressure plate (5) in order to displace the pressure plate (5) in the axial direction (4)

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

a pressure plate (5) that can be displaced to a limited extent in an axial direction (4) of the friction clutch with respect to a counter-pressure plate (2) for frictionally locking a clutch disc (6)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3565984B1Friction clutch
Publication Date: 2021.02.17 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP3565984B1 patent drawingFigure 1~2
  • EP3565984B1 patent drawingFigure 3~4
  • EP3565984B1 patent drawingFigure 5~6

AI summary

The invention relates to a friction clutch for a drive train of a motor vehicle, at least comprising a counter pressure plate, a clutch cover connected to the counter pressure plate, and a pressure plate which can move in a limited manner in relation to the counter pressure plate in an axial direction of the friction clutch, and which is for frictionally clamping a clutch disc between the counter pressure plate and the pressure plate, wherein at least one disc spring centring device is provided on the clutch cover, via which a disc spring is retained in a centred position in relation to a rotational axis of the friction clutch, wherein at least one leaf spring is provided, via which the pressure plate is connected to the clutch cover in a rotationally fixed manner and such that it can move in a limited manner in the axial direction, wherein, in a first section, the at least one leaf spring extends from a first connection to the pressure plate, at least along the peripheral direction, up to a second connection to the disc spring centring device, and wherein, in a second section, the leaf spring extends further from the second connection, at least in the peripheral direction, up to a first end of the leaf spring, wherein, with the second section, the leaf spring contacts the disc spring with a contact point of the leaf spring.