Progressive Clutch Disc Pad Layout for Smooth Torque Engagement

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Solution Overview

Problem

Existing friction clutch discs experience uncontrolled deformation and increased wear due to limited friction pads and high contact pressure, leading to discomfort and reduced durability, along with high stiffness that degrades vehicle comfort and performance.

Innovation Solution

A progressive device with angular segment-shaped friction pads fixed on adjacent progressiveness blades, distributed circumferentially on a support web, increasing the friction surface area and fixing points, and featuring a radial offset to enhance mechanical resistance and durability, while maintaining parallelism to prevent uncontrolled deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If segment-shaped friction pads are used in a progressive engagement device, then the clutch mechanism can apply increasing axial compressive force during re-engagement phase, but the friction pads deform in an uncontrolled manner creating discontinuities in torque transmission and chattering phenomenon

Engineering Contradiction:
Improvegradual torque transmission during re-engagementVSAvoidalignment stability of friction pads
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The friction pads are divided into multiple angular segments distributed circumferentially on the support web. Each segment is fixed by two adjacent progressive blades, creating smaller controlled deformation units that maintain alignment stability while enabling progressive engagement. This segmentation allows the clutch to apply increasing axial force gradually without uncontrolled deformation of large single pads.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The friction pads are arranged on both faces of the support web in a circumferential distribution pattern, transitioning from a single-plane to a multi-dimensional arrangement. This spatial distribution increases the friction surface area and provides multiple fixing points through adjacent blades, enhancing alignment stability while maintaining progressive engagement capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If a limited number of segment-shaped friction pads are used, then the progressive engagement device can be manufactured, but the contact pressure is higher than with annular friction surfaces resulting in increased wear and reduced clutch durability

Engineering Contradiction:
Improvenumber of friction padsVSAvoidclutch durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The friction surface is segmented into multiple angular pads distributed circumferentially, increasing the total friction surface area compared to traditional annular designs. This segmentation distributes the contact pressure across multiple smaller surfaces, reducing wear on each individual pad while maintaining the progressive engagement function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Friction pads are arranged on both faces of the support web in a circumferential pattern, utilizing the three-dimensional space available. This multi-face arrangement significantly increases the total friction surface area, distributing the clamping force and reducing contact pressure, thereby improving clutch durability without increasing device complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Device complexity

If the number of folds on progressive damping blades is limited, then the structure remains simple, but the overall stiffness of the progressive damping system is high degrading vehicle comfort

Engineering Contradiction:
Improvenumber of folds on bladesVSAvoidvehicle comfort
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The progressive damping blades are segmented with multiple folds instead of limited folds, creating a multi-layered progressive structure. Each fold acts as an independent damping element, allowing gradual deformation under load. This segmentation provides progressive engagement with controlled stiffness, improving vehicle comfort while maintaining structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The number of folds on the progressive damping blades is increased to change the mechanical parameters of the system. More folds create a softer, more progressive damping characteristic, reducing the overall stiffness of the system. This parameter change allows the clutch to engage more smoothly, improving vehicle comfort without significantly increasing device complexity.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If friction pads are fixed by a single progressive blade, then the assembly is simple, but the geometric assembly defects are reduced and centrifugal resistance is insufficient

Engineering Contradiction:
Improveassembly simplicityVSAvoidcentrifugal resistance
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

Each friction pad is fixed by two adjacent progressive blades instead of a single blade, merging the support function of multiple blades. This dual-blade fixation provides redundant support, reducing geometric assembly defects and enhancing centrifugal resistance. The combined support from adjacent blades creates a more robust attachment that maintains alignment under centrifugal forces.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The friction pads are fixed at multiple circumferential positions on both faces of the support web, creating a distributed fixation pattern. This multi-dimensional arrangement of fixing points increases the overall structural strength and centrifugal resistance, while the regular pattern maintains manufacturing simplicity through standardized assembly procedures.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 solution improves the durability and mechanical strength of the friction clutch disc, reduces geometric assembly defects, and enhances the resistance to centrifugal forces, resulting in smoother torque transmission and improved vehicle comfort by controlling pad deformation and distributing stress evenly.

Implementation Method 1

friction pads arranged circumferentially on both faces of the support web... friction pads distributed on the external part of the support web

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

each progressive blade being mounted on the periphery of a torque transmission web... the other having a fold that deforms radially when the clutch mechanism is closed

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

Helical compression springs are arranged circumferentially between the guide washers and the disc. Torque transmission and the filtering of engine irregularities are achieved through the successive compression and release of these springs

Methodology Applied
Scientific EffectSpring compression: Spring

Implementation Method 4

increasing the number of fixing points, thus improving the centrifugal resistance of the friction clutch disc

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3734101B1Progressive device for a friction clutch disc and friction clutch disc comprising such device
Publication Date: 2023.12.06 VALEO EMBRAYAGES SAS
  • EP3734101B1 patent drawingFigure 1
  • EP3734101B1 patent drawingFigure 2
  • EP3734101B1 patent drawingFigure 3~4

AI summary

The invention relates to a progressive device (10) for a friction clutch disc, comprising: a support web (11, 11a) with a central axis of rotation (X) in which a central annular part (12, 12a) is adapted to cooperate with a torsional vibration damper (2) and an external part (13, 13a) carries progressive blades (20, 20a), said progressive blades extending circumferentially between a cooperation zone (14, 14a) of the external part of the support web and a free end (21, 21a), and friction pads (30) arranged circumferentially on both faces of the support web (11, 11a), distributed on the external part of the support web.