Flexible Shaft Coupling with Dual-Hardness Elastomer

Solution Overview

Problem

Flexible shaft couplings face a trade-off between efficiently transmitting torque and accommodating positional deviations, with soft rubber materials increasing rotational angular difference and reducing durability, while hard rubber materials reduce positional deviation accommodation capabilities and cause stress-related fatigue.

Innovation Solution

A flexible coupling design featuring a first elastomer member with high rubber hardness for torque transmission and a second elastomer member with lower rubber hardness for accommodating positional deviations, with both materials being strategically positioned between claws on the shaft coupling members to manage stress and deformation effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If soft rubber material is used for the elastomer member to accommodate positional deviation, then the capability to accommodate radial offset, angular offset and axial offset is improved, but the rotational angular difference increases to unacceptable level and durability is reduced

Engineering Contradiction:

Improvecapability to accommodate positional deviationVSAvoiddurability of elastomer member

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The elastomer member is divided into multiple segments or layers with different rubber hardness values. The first elastomer member has higher rubber hardness while the second elastomer member has lower rubber hardness, allowing each segment to perform its specific function optimally without the negative effects affecting the entire component.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the elastomer member are assigned different rubber hardness properties. The first elastomer member with higher hardness is positioned to handle torque transmission, while the second elastomer member with lower hardness is positioned to accommodate positional deviations, creating local quality variations that optimize overall performance.

Inventive Principle:

Principle #3Local quality

2Reliability

If hard rubber material is used for the elastomer member to maintain durability, then the rotational angular difference is controlled within acceptable levels, but the capability to accommodate significant positional deviation is reduced

Engineering Contradiction:

Improvedurability of elastomer memberVSAvoidcapability to accommodate positional deviation

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The elastomer member is divided into multiple segments or layers with different rubber hardness values. The first elastomer member has higher rubber hardness while the second elastomer member has lower rubber hardness, allowing each segment to perform its specific function optimally without the negative effects affecting the entire component.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the elastomer member are assigned different rubber hardness properties. The first elastomer member with higher hardness is positioned to handle torque transmission, while the second elastomer member with lower hardness is positioned to accommodate positional deviations, creating local quality variations that optimize overall performance.

Inventive Principle:

Principle #3Local quality

3Reliability

If elastomer material is placed only in parts loaded solely by torque to avoid stress from positional deviations, then durability is improved, but manufacturing complexity and cost increase significantly

Engineering Contradiction:

Improvedurability of elastomer memberVSAvoidcomplexity of molding die

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The elastomer member is divided into multiple segments or layers with different rubber hardness values. The first elastomer member has higher rubber hardness while the second elastomer member has lower rubber hardness, allowing each segment to perform its specific function optimally without the negative effects affecting the entire component.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the elastomer member are assigned different rubber hardness properties. The first elastomer member with higher hardness is positioned to handle torque transmission, while the second elastomer member with lower hardness is positioned to accommodate positional deviations, creating local quality variations that optimize overall performance.

Inventive Principle:

Principle #3Local quality

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 design enhances torque transmission performance, accommodates positional deviations, and improves durability by minimizing excessive angular deviation and axial loading, thereby extending the service life of the shaft coupling.

Implementation Method 1

a first elastomer member (82) having a relatively high rubber hardness is circumferentially interposed between the first and second claws

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

a second elastomer member (84, 86) having a lower rubber hardness than the first elastomer member is interposed between the surface portion of the first shaft coupling member and the second claw and/or between the surface portion of the second shaft coupling member and the first claw

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS8992334B2Flexible shaft coupling and method of manufacturing the same

Publication Date: 2015.03.31 MIKI PULLEY

AI summary

A flexible shaft coupling demonstrates a high performance in transmitting torque and accommodating positional deviations, and is yet highly durable. A first elastomer member (82) having a relatively high rubber hardness is circumferentially interposed between a first claw (32) of a first shaft coupling member (20) and a second claw (62) of a second shaft coupling member (50), and a second elastomer member (84, 86) having a lower rubber hardness than the first elastomer member is interposed between a surface portion (end surface) (30) of the first shaft coupling member (20) and the second claw (62) and/or between a surface portion (end surface) (60) of the second shaft coupling member (50) and the first claw (32).