Multi-Material Shaft Disconnect Using Predictable Shear Failure
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Solution Overview
Problem
Conventional shaft disconnect designs for electrical machine shafts often lack space for conventional designs and require improved thermal and over-torque management.
Innovation Solution
A shaft design featuring a disconnect portion with distinct material properties that can shear under mechanical, electrical, or thermal loads, manufactured using additive processes with varying material blends and shapes, such as a double cone configuration, to ensure physical disconnection between sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional thinned portion or mechanical disconnect is used, then thermal/over-torque disconnect is achieved, but space requirements increase and device complexity increases
Solution Approach 1:
The patent changes the material parameters of the shaft by incorporating a disconnect portion with different material properties (lower melting point, lower shear strength) than the main shaft material. This allows the disconnect to occur at predetermined conditions without requiring complex mechanical mechanisms or thinned portions, thereby achieving thermal/over-torque disconnect while reducing device complexity
Solution Approach 2:
The patent uses composite material construction where the shaft includes portions of different materials: the main shaft material and the disconnect portion material with lower strength properties. This composite approach enables the shaft to have both high strength where needed and predictable failure points, achieving reliable disconnect functionality without increasing device complexity
2Reliability
If a conventional thinned portion or mechanical disconnect is used, then thermal/over-torque disconnect is achieved, but the available space is reduced
Solution Approach 1:
The patent achieves disconnect functionality by changing material parameters rather than reducing geometric dimensions. The disconnect portion has the same or greater radius than the main shaft but contains material with lower melting point and shear strength, enabling thermal/over-torque disconnect without requiring thinned portions or additional space
3Ease of manufacture
If additive manufacturing with gradient portions is used, then manufacturing flexibility and material distribution are improved, but manufacturing process complexity increases
Solution Approach 1:
The patent applies local quality by creating gradient portions where the material composition varies spatially along the shaft length. The second material content increases along the shaft length direction, creating a gradual transition in material properties that enables predictable disconnect behavior while being manufactured through additive processes
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 effectively manages thermal and over-torque conditions by ensuring the disconnect portion shears predictably, preventing damage to electrical machines without the need for traditional thinned sections, and can be manufactured in a continuous process.
Implementation Method 1
the disconnect portion is configured to shear under one or more predetermined operational conditions
Implementation Method 2
The second material properties can include a second melting point and/or softening temperature that is less than a first melting point and/or softening temperature
Data Source
AI summary
A shaft can include a first portion comprising a first material having first material properties, a disconnect portion comprising at least some of a second material having second material properties, and a third portion comprising a third material having third material properties. The disconnect portion can be positioned between the first portion and the third portion, the three material properties being configured such that the first portion is physically disconnected from the third portion in response to failure of the disconnect portion under at least one of a mechanical load and/or an electrical load and/or thermal load.