Friction Clutch Wear Inspection via External Test Pointer

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Solution Overview

Problem

Existing friction clutches lack a simple and reliable method to check the wear state of clutch discs without disassembly, making it difficult to assess wear and predict remaining life.

Innovation Solution

Incorporating a test device with a reference mark and a visible test pointer that indicates the wear state of the clutch disc by showing the relative position of the pressure plate to the counter-plate, allowing for external visual inspection without disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the friction clutch is assembled and sealed, then protection from harmful factors is improved, but ease of operation for wear checking deteriorates

Engineering Contradiction:
Improveprotection from harmful factorsVSAvoidease of operation
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The friction clutch assembly is segmented into functional components: a sealed clutch assembly portion containing the clutch disc, pressure plate, and counter plate, and a separate accessible test device portion. The test device includes a test pointer attached to the pressure plate that extends through or beyond the clutch cover, allowing wear indication without compromising the sealed protection of the internal components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The test pointer serves as an intermediary element that transmits information from the sealed internal components to the external environment. It is attached to the pressure plate inside the sealed assembly but extends outward to allow visual inspection, acting as a mediator that provides wear information without requiring disassembly or exposing internal components to contaminants.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the clutch assembly is sealed and riveted, then reliability is improved, but ease of repair deteriorates

Engineering Contradiction:
ImprovereliabilityVSAvoidease of repair
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The clutch assembly is designed with segmented functionality where the test device is integrated as a separate inspectable component. The clutch cover incorporates a test window or opening that allows the test pointer to be visible and accessible, enabling repair personnel to check wear conditions without drilling out spacer bolts or disassembling the sealed clutch assembly, thus maintaining reliability while improving ease of repair.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The test pointer acts as an intermediary that provides wear information to external observers without requiring breach of the sealed clutch assembly. This allows the clutch to maintain its reliable sealed construction while enabling easy inspection and assessment of wear conditions for repair planning.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the test pointer is made visible from outside, then ease of operation for wear checking is improved, but device complexity increases

Engineering Contradiction:
Improveease of operationVSAvoiddevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The test device is merged with existing clutch components rather than being a separate addition. The test pointer is attached to the pressure plate, which is already part of the clutch assembly, and the test window is incorporated into the clutch cover. This integration allows wear checking without adding significant complexity to the overall device structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The clutch cover serves multiple functions: it protects the internal components, provides structural support, and incorporates a test window for wear inspection. The pressure plate also serves its primary function of applying friction force while simultaneously carrying the test pointer attachment point. This multi-functionality reduces the need for additional separate components.

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

Enables easy and reliable assessment of clutch disc wear from the outside of the assembled friction clutch, allowing for timely prediction of remaining life and avoiding the need for disassembly.

Implementation Method 1

a pressure plate (20) which can be moved axially within the clutch assembly by a disc spring (28)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a clutch disc (26) having a friction lining (24) on its friction surface

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3303864B1Friction clutch
Publication Date: 2019.07.10 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP3303864B1 patent drawingFigure 1~2
  • EP3303864B1 patent drawingFigure 3~5

AI summary

The invention relates to a friction clutch (10) for coupling a drive shaft of a motor vehicle engine to at least one transmission input shaft of a motor vehicle transmission, comprising: a clutch cover (12); a counter plate (14) secured to the clutch cover (12); a pressure plate (20), which can be moved axially in relation to the counter plate (14), for frictionally pressing a clutch disc (26) between the counter plate (14) and the pressure plate (20); an actuation element (22), which can be mounted on the clutch cover (12) in a tiltable manner, for moving the pressure plate (20); and a checking unit (42), having a reference mark (44) and a check indicator (46), for checking the wear state of the clutch disc (26), wherein the wear state of the clutch disc (26) can be visually checked using the checking unit (42) from outside the assembled friction clutch (10).