Friction Disc Misalignment Compensation via Washer Friction Torque

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Solution Overview

Problem

Traditional traction transmission systems face challenges in accommodating both angular and radial misalignments between the crankshaft and gearbox shaft axes, leading to noise, vibration, and mechanical failure due to the limitations of existing compensation mechanisms, particularly in constrained mechanical environments with dual mass flywheels.

Innovation Solution

A device comprising an annular disc with an inner and outer washer system, where the inner washer is retained on the hub and the outer washer is mounted coaxially in a cover, allowing for radial and angular movement, with an energy accumulator providing a circumferentially distributed load to control misalignment-induced displacement through friction torque, enhancing the friction torque and reducing axial tightening forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If springs and internal toothing are used to control radial displacement of the hub, then misalignment compensation is improved, but device complexity and cost increase

Engineering Contradiction:
Improvemisalignment compensationVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the spring element from the misalignment compensation mechanism and replaces it with a simpler geometry-based solution. The hub is given freedom of radial movement without active spring control, eliminating the need for complex spring-mechanism assemblies while maintaining compensation functionality through passive geometric design

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the misalignment compensation into two independent functions: angular misalignment is compensated by the tilted veil geometry, while radial misalignment is handled by the hub's freedom of radial movement. This segmentation allows each function to be addressed with simpler, dedicated mechanisms rather than a single complex system

Inventive Principle:
Principle #1Segmentation

2Reliability

If a large external diameter veil is used to accommodate misalignments, then misalignment compensation is improved, but the device bulk increases causing interference in constrained environments

Engineering Contradiction:
Improvemisalignment compensationVSAvoiddevice bulk
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent resolves the spatial conflict by tilting the veil at an angle relative to the crankshaft axis. This angular orientation allows the veil to accommodate angular misalignment compensation in one dimension while maintaining a compact radial profile in another dimension, preventing interference with surrounding components in constrained environments

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

3Reliability

If a rotating friction veil is used to limit angular offsets, then angular misalignment is improved, but radial offset control is lost leading to noise and vibration

Engineering Contradiction:
Improveangular offset limitationVSAvoidnoise and vibration
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the misalignment compensation into two independent functions: angular misalignment is compensated by the tilted veil geometry, while radial misalignment is handled by the hub's freedom of radial movement. This segmentation allows each function to be addressed with simpler, dedicated mechanisms rather than a single complex system

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary damping element between the hub and veil that actively controls radial vibrations and noise. This intermediary component absorbs harmful vibrations and noise generated by radial offset variations, preventing them from propagating through the system while allowing the veil to focus on angular misalignment compensation

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively compensates for up to 2 mm radial and 2° angular misalignments, reducing the risk of deformation and noise, while maintaining alignment and increasing the friction torque to filter engine vibrations effectively, even in neutral transmission phases.

Implementation Method 1

The displacement of the hub resulting from the misalignment causes the relative radial displacement of said washers and is controlled by their mutual friction torque

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

an energy accumulator providing a circumferentially distributed load to control misalignment-induced displacement through friction torque

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3404278B1Device for accommodating misalignments between the crankshaft and the input shaft of the gearbox and friction disc provided with such a device
Publication Date: 2019.08.28 VALEO EMBRAYAGES SAS
  • EP3404278B1 patent drawingFigure 1A
  • EP3404278B1 patent drawingFigure 1B~2A
  • EP3404278B1 patent drawingFigure 2B~2C

AI summary

The invention relates to: - a device for accommodating (A) the radial or angular misalignment between the respective axes (Y, Z) of a crankshaft and a gearbox input shaft in a motor vehicle transmission system comprising, an annular disc (2) intended to be rotationally coupled with the crankshaft, a hub (1) intended to be, on the one hand, rotationally coupled to the gearbox input shaft and, on the other hand, engaged with freedom of movement in said annular disc (2), characterized in that it comprises, at least one inner washer (3) retained on the periphery of the hub (1) and at least one outer washer (4) mounted coaxially in a cover (5) fixed to said disc (2) by trapping said washers (3, 4) in a contiguous manner such that the movement of the hub (1) resulting from the misalignment causes the relative radial displacement of said washers (3, 4).4) and be controlled by their mutual friction couple, - a friction disc (6) equipped with said device and, - a transmission system comprising said disc.