Friction Disc Hub Design for False Twist Thermal Management

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Solution Overview

Problem

Existing friction disks in false twist devices experience significant wear and heat generation during the twisting process, leading to reduced service life and increased maintenance costs, with previous attempts to improve wear resistance compromising friction coefficients or requiring impractical replacement procedures.

Innovation Solution

The friction disk design features a custom-ground race with a specific width dimension and a hub with a circumferential approach that minimizes surface temperature, incorporating a PBT hub with a PU layer of minimal thickness and enhanced cooling through a fan-shaped hub design with air passages for improved airflow and thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the friction discs rotate at high circumferential speeds to generate false twist, then the twisting performance is improved, but the heat generation and wear increase

Engineering Contradiction:
Improvefalse twist generation efficiencyVSAvoidsurface temperature of friction disc
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The friction disc is divided into two separate components: a hub and a race (friction layer). This segmentation allows the race to be optimized for friction performance while the hub can be designed for thermal management and structural support, resolving the contradiction between high-speed operation and heat generation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The friction disc uses a composite structure combining a polyurethane layer (race) with a hub made of different material properties. The PU layer provides the necessary friction characteristics while the hub structure manages heat dissipation, allowing high circumferential speeds without excessive heat generation.

Inventive Principle:
Principle #40Composite materials

2Duration of action of stationary object

If the race is made with thicker PU layer to reduce wear, then the service life is improved, but the manufacturing cost and complexity increase

Engineering Contradiction:
Improveservice life of friction discVSAvoidmanufacturing complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

By separating the race from the hub, the wear-resistant PU layer can be applied only where needed (on the friction surface) rather than throughout the entire component. This reduces material usage and simplifies manufacturing compared to making the entire disc from thick wear-resistant material.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention optimizes the thickness parameter of the PU layer to achieve the minimum necessary for wear resistance while maintaining cost-effectiveness. This parameter optimization balances service life improvement with manufacturing simplicity.

Inventive Principle:
Principle #35Parameter changes

3Ease of repair

If the race and hub are designed as separate components to reduce overhaul costs, then the replacement flexibility is improved, but the labor required for race replacement becomes impractical

Engineering Contradiction:
Improvereplacement flexibilityVSAvoidlabor intensity for race replacement
Core Design Contradiction:
Ease of repairVSEase of operation

Solution Approach 1:

The race and hub are merged into a single integrated friction disc component that is mounted as one unit on the shaft. This eliminates the practical difficulties of separate race replacement while maintaining the benefits of modular design through the ability to replace the entire disc assembly quickly.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated friction disc design serves multiple functions: it provides friction surface, structural support, and thermal management in a single component. This multi-functionality simplifies the replacement process while maintaining all necessary performance characteristics.

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

4Duration of action of stationary object

If ceramic nanoparticles are embedded in polyurethane to reduce wear, then the service life is improved, but the coefficient of friction decreases

Engineering Contradiction:
Improveservice life of friction discVSAvoidcoefficient of friction
Core Design Contradiction:
Duration of action of stationary objectVSForce

Solution Approach 1:

The friction disc uses different material compositions in different regions: the PU layer is formulated with specific properties for optimal friction, while the hub provides structural support. This local differentiation allows wear resistance and friction coefficient to be optimized independently in their respective zones.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention uses a composite structure where the PU layer can be formulated with or without ceramic additives depending on the specific performance requirements. The composite design allows balancing wear resistance and friction coefficient by adjusting the composition and thickness of the PU layer relative to the hub.

Inventive Principle:
Principle #40Composite materials

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 design reduces surface temperature, enhances the stability and longevity of the friction disks, improves running behavior, and allows for energy savings by minimizing heat development and wear, while maintaining effective frictional resistance and dimensional stability.

Implementation Method 1

enhanced cooling through a fan-shaped hub design with air passages for improved airflow and thermal conductivity

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

enhanced cooling through a fan-shaped hub design with air passages for improved airflow and thermal conductivity

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

The frictional force between the yarn and the friction discs, which rotate in a plane transverse to the yarn travel direction, continuously generates the desired false twist

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3739091B1Friction disc for false twisting device
Publication Date: 2024.04.17 RIETER COMPONENTS GERMANY GMBH
  • EP3739091B1 patent drawingFigure 1
  • EP3739091B1 patent drawingFigure 2~3
  • EP3739091B1 patent drawingFigure 4~6

AI summary

The invention relates to a friction disc (5) for a false twist device (1) with an annular hub (6) on which a circular running ring (9) formed by a PU layer with a minimum wall thickness necessary for a secure positive fit can be fixed, wherein the hub (6) has a circumferential support ring (7) and a central bore (8) by means of which the friction disc (5) can be fixed on one of the shafts (4) of the false twist device (1).To ensure better dimensional and shape stability over a long service life of the friction disc (5), the invention provides that the formed running ring (9) fixed on the hub (6) is ground according to a predefinable profile such that the flanks (10) of the running ring (9) have a predefinable width dimension (BFL) after the grinding process, and/or the hub (6) has a circumferential projection (11) spaced apart from the support ring (7) for the contact of the definable PU layer, wherein a cross-sectional width (BA) of the projection (11) is smaller than a cross-sectional width (BS) of the support ring (7).