Shaft Joint Phase Adjustment Without Coupling Slippage

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Solution Overview

Problem

The existing coupling devices for transmitting rotational force between shafts face challenges in easily adjusting the relative rotational phase and preventing slippage, particularly when the fastening bolt hole is transformed into a long hole, leading to non-uniform contact and transmission of force.

Innovation Solution

A coupling device configuration that includes a base member and a shaft mounting member with a long hole, where the intermediate member is fixed to the base member, preventing the restoring force from acting on the shaft mounting member and allowing for easy adjustment of the relative rotational phase by shifting the position of the fastening device through the long hole.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the fastening bolt hole is transformed into a long hole to enable easy rotational phase adjustment, then the ease of operation is improved, but the reliability deteriorates due to non-uniform contact area and fastening force distribution causing slippage

Engineering Contradiction:
Improverotational phase adjustmentVSAvoidfastening stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The second coupling member is divided into two separate members: a base member that receives the restoring force from the metal plate spring, and a shaft mounting member that has the long hole for rotational phase adjustment. This segmentation isolates the restoring force action to the base member, preventing slippage while maintaining adjustment capability through the long hole in the shaft mounting member.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the fastening bolt hole is transformed into a long hole to allow rotational phase shifting, then the adaptability is improved, but the strength deteriorates due to non-uniform force transmission

Engineering Contradiction:
Improverotational phase adjustmentVSAvoidfastening strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

By separating the base member and shaft mounting member, the restoring force from the metal plate spring acts on the base member which has sufficient contact area and strength. The shaft mounting member with the long hole can rotate freely for phase adjustment without compromising overall fastening strength, as the critical force transmission occurs through the base member connection.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If the intermediate member is flexed to absorb misalignment between shafts, then the adaptability is improved, but the harmful factors increase due to restoring force acting on the fastening bolt causing slippage

Engineering Contradiction:
Improvemisalignment absorptionVSAvoidrestoring force induced slippage
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The harmful restoring force generated by the flexible metal plate spring is extracted and directed to act on the base member through dedicated fastening bolts, rather than on the shaft mounting member with the long hole. This separates the force transmission path from the adjustment mechanism, eliminating slippage while preserving misalignment absorption capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The coupling member is segmented into base member and shaft mounting member, allowing the restoring force to be contained and managed at the base member level, preventing it from causing slippage in the shaft mounting member while maintaining the flexibility needed for misalignment absorption.

Inventive Principle:
Principle #1Segmentation

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 easy adjustment of the relative rotational phase between shafts while preventing slippage by ensuring the restoring force acts on the base member, maintaining uniform force transmission and enhancing the coupling device's strength and ease of use.

Implementation Method 1

an intermediate member disposed between the first shaft and the second shaft in an extension direction of an axis of the coupling device, and configured to absorb misalignment between the first shaft and the second shaft

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3943772B1Shaft joint device, and rotational phase adjusting method for shaft joint device
Publication Date: 2024.07.03 MITSUBISHI HEAVY IND ENGINE & TURBOCHARGER LTD
  • EP3943772B1 patent drawingFigure 1
  • EP3943772B1 patent drawingFigure 2
  • EP3943772B1 patent drawingFigure 3

AI summary

A shaft joint device configured to transmit a rotational force between a first shaft and a second shaft is provided with a first joint member to be attached to the first shaft, a second joint member to be attached to the second shaft, and an intermediate member which is disposed between the first joint member and the second joint member, and which is configured to allow misalignment between the first shaft and the second shaft, wherein the second joint member includes: a base member configured to be fixed to the intermediate member by means of a first fastening device; and a shaft attachment member which is configured to be attached to the second shaft without being capable of relative rotation, which has an elongated hole extending in the circumferential direction of an axis, and which is configured to be detachably fixed to the base member by means of a second fastening device which is inserted through the elongated hole.