Helical-Slot Hub-Shaft Coupling for Backlash-Free Torque Transfer
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Solution Overview
Problem
Existing hub-shaft couplings are prone to backlash due to tolerances, and existing solutions either disintegrate the shaft or require complex hydraulic systems.
Innovation Solution
A backlash-free hub-shaft coupling design that includes an axially intermediate section with inclined slits, converting axial compression force into rotational force to suppress backlash, without disintegrating the shaft or requiring hydraulic systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inclined contact faces are used to suppress backlash, then backlash is suppressed, but the shaft is disintegrated into two pieces and the structure becomes complex
Solution Approach 1:
The intermediate section is segmented into multiple axial segments that can rotate relative to each other. This segmentation allows the shaft to generate rotational force to suppress backlash without disintegrating into separate pieces, resolving the contradiction between backlash suppression and structural integrity.
Solution Approach 2:
The intermediate section is designed to be dynamically rotatable relative to the front and rear sections. This dynamic capability allows the intermediate section to convert axial compression into rotational force for backlash suppression, while the segments remain connected as part of a unified shaft structure.
2Force
If a hydraulic cylinder is used to generate rotational force, then rotational force is generated, but the system requires hydraulic infrastructure and becomes mechanically complex
Solution Approach 1:
The intermediate section itself serves as the mechanism to generate rotational force by converting axial compression into rotation. This self-service approach eliminates the need for external hydraulic cylinders or complex mechanical systems, resolving the contradiction between generating rotational force and maintaining system simplicity.
Solution Approach 2:
The patent replaces the hydraulic cylinder mechanism with a purely mechanical solution where the intermediate section's geometry and material properties enable it to convert axial compression into rotational force, eliminating the need for hydraulic infrastructure.
3Reliability
If an axially intermediate section with inclined slits is used, then axial compression force is converted into rotational force to suppress backlash, but the structure becomes more complex
Solution Approach 1:
The inclined slits are introduced only in the intermediate section where they are needed for force conversion, while the front and rear sections maintain their simple fluted structures. This localized application resolves the contradiction by adding complexity only where necessary for backlash suppression.
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 achieves a backlash-free coupling with controlled backlash-suppressing force, reduced complexity, and improved balancing and repeatability, while minimizing hysteresis and stress under cyclic loads.
Implementation Method 1
an axially intermediate section (35) which is arranged between a front and a rear fluted section and is capable to convert axial compression force into a relative rotational force
Data Source
AI summary
In a coupling arrangement of the hub-shaft type, at least one of hub and shaft includes two sections, these two sections being connected by an intermediate flexible section. The flexibility of the intermediate section is attained by circumferentially provided helical slots. The flexible intermediate section twists the twistable section relative to the fixed section if a nut is screwed on the terminal thread with increasing torque. Thereby, any play existing in the coupling, i.e. between the flutes of hub and shaft, is removed. By further increasing the torque, the coupling is even backlash-free in both rotational directions up to at least the torque excess.