Flexible Coupling with Cam-Actuated Clamping for Multi-Diameter Shafts

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Solution Overview

Problem

Existing couplings for rotating shafts face challenges in connecting shafts of different diameters and types, requiring custom production, which is time-consuming and costly, and can lead to damage due to vibrations and fretting corrosion, especially when high torsional stresses are involved.

Innovation Solution

A flexible coupling design featuring identical hubs and flexible elements with circumferential seats and screw clamping means, including cam surfaces, allowing for easy assembly and disassembly without welding, and accommodating various shaft diameters and types with a limited number of stock parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If couplings are prepared in advance with identical standard type hubs, then mass production efficiency is improved, but the ability to connect shafts of different diameters and types deteriorates

Engineering Contradiction:
Improvemass production efficiencyVSAvoidability to connect shafts of different diameters
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The coupling is divided into separate modular components: standard hubs, flexible elements, and adaptor rings. This segmentation allows the standard hubs to be mass-produced while adaptors are configured for specific shaft requirements, resolving the contradiction between mass production efficiency and adaptability to different shaft dimensions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Adaptor rings are introduced as intermediary components between the standard hub bore and the shaft. These adaptors enable connections to shafts of various diameters and types without requiring custom hubs, thus maintaining mass production benefits while achieving versatility.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If adaptor rings are used between the bore of the hub and the shaft, then adaptability to different shaft diameters is improved, but reliability under high torsional stresses deteriorates

Engineering Contradiction:
Improveadaptability to different shaft diametersVSAvoidreliability under high torsional stresses
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The adaptor rings feature conical friction surfaces with specific geometric curvature. This conical geometry distributes torsional stresses more evenly across the contact area and provides self-aligning properties, enhancing the reliability of the adaptor connection under high torsional loads while maintaining adaptability to different shaft diameters.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Adaptability or versatility

If hubs are modified to enlarge bores during operation, then adaptability to different shaft diameters is improved, but the integrity of the flexible element and welds deteriorates due to vibrations

Engineering Contradiction:
Improveadaptability to different shaft diametersVSAvoidintegrity of flexible element and welds
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

Adaptor rings are pre-configured with the correct bore diameter matching the target shaft before assembly. This eliminates the need for on-site bore enlargement operations that generate harmful vibrations, thereby protecting the integrity of the flexible element and welds while achieving adaptability to different shaft dimensions.

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If custom couplings are made to order for different shaft types, then adaptability to specific shaft requirements is improved, but production time and costs deteriorate

Engineering Contradiction:
Improveadaptability to specific shaft requirementsVSAvoidproduction time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The coupling system is segmented into standardized components (hubs, flexible elements) that can be mass-produced, and configurable components (adaptor rings) that are quickly selected and assembled. This reduces production time compared to completely custom couplings while maintaining adaptability to specific shaft requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The standard hub design serves multiple functions: it can connect to various shaft types through different adaptor rings, and it maintains consistent mounting interfaces for flexible elements. This universality allows a single hub design to satisfy many different coupling applications, reducing the need for custom production.

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

5Ease of operation

If adaptor rings are used for connecting hubs to shafts, then ease of assembly is improved, but risk of fretting corrosion and seizing deteriorates

Engineering Contradiction:
Improveease of assemblyVSAvoidfretting corrosion and seizing
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The conical friction surfaces of the adaptor rings provide self-aligning properties that distribute contact stresses more uniformly, reducing localized fretting. The geometric configuration minimizes relative micro-movements between contacting surfaces, thereby reducing fretting corrosion risk while maintaining ease of assembly.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The adaptor rings are designed with optimized friction surface parameters including cone angle, surface area, and material properties. These parameter changes increase the frictional grip and distribute loads more evenly, preventing seizing while maintaining ease of assembly and disassembly.

Inventive Principle:
Principle #35Parameter changes

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 efficient production and assembly of couplings for both standard and custom applications, reducing costs and preventing damage to connected shafts, while ensuring reliable transmission of motion under high torsional stresses.

Implementation Method 1

the retaining means include one or more cam surfaces suitable to receive in abutment corresponding opposed cam surfaces of screw clamping means

Methodology Applied
Scientific EffectCam mechanism: Cam

Implementation Method 2

a flexible element produced in bellows form or a component with helical bands

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2102519B1Flexible coupling
Publication Date: 2010.04.28 SIT SPA
  • EP2102519B1 patent drawingFigure 1
  • EP2102519B1 patent drawingFigure 2~3
  • EP2102519B1 patent drawingFigure 4~5

AI summary

A coupling for transmitting motion between two rotating shafts, including a pair of hubs and a flexible element, wherein each of the hubs includes at least one circumferential seat facing towards the flexible element and suitable to receive therewithin an end of the flexible element. To fasten the flexible element to each of the hubs there are provided retaining means, which include one or more cam surfaces suitable to receive in abutment corresponding opposed cam surfaces of screw clamping means.