Over-Running Shaft Core Assembly for Transient Torque Isolation
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Solution Overview
Problem
Existing rotating machines, such as vehicle alternators, experience accelerated wear and belt ejection due to transient torque loads, which are often addressed with costly external over-running pulleys that reduce generator reliability.
Innovation Solution
An over-running shaft core assembly integrates over-running capability directly into the rotating assembly, using friction elements to raise a torque threshold for clutch engagement, reducing wear on bearings and sprags, and allowing drop-in interchangeability with legacy systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If an external over-running pulley is fitted to the rotating shaft, then transient torque loads are reduced, but the generator reliability decreases and cost increases
Solution Approach 1:
The over-running clutch mechanism is integrated directly into the rotating assembly, merging the clutch housing with the rotor assembly. This eliminates the need for external over-running pulleys and their associated clutching mechanisms, thereby improving reliability by removing external failure points while still managing transient torque loads.
Solution Approach 2:
The clutch mechanism is extracted from the external drive system and embedded within the rotating assembly itself. This allows the clutch to operate independently of belt-driven transient loads, isolating it from the harmful forces that cause bearing wear and failures in external systems.
2Duration of action of moving object
If friction elements are added to raise torque threshold, then clutch wear is reduced, but device complexity increases
Solution Approach 1:
Friction elements are strategically positioned at specific locations within the clutch mechanism where they can most effectively raise the torque threshold. This localized approach allows the clutch to ride through minor torque transients without engaging, reducing wear on sprags and rolling elements while adding minimal complexity to the overall device.
Solution Approach 2:
The friction elements modify the torque threshold parameter of the clutch mechanism, changing its engagement characteristics. By adjusting this parameter, the clutch can distinguish between minor transient loads and significant overload conditions, extending clutch life while maintaining a relatively simple structure.
3Reliability
If over-running capability is integrated into rotating assembly, then cost is reduced and reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The rotating assembly is segmented into distinct functional components: the clutch mechanism, the rotor assembly, and the stator assembly. This segmentation allows each component to be manufactured and assembled separately using standard machining processes, reducing manufacturing complexity while achieving the reliability benefits of integration.
Solution Approach 2:
The rotating assembly is designed to perform multiple functions: electrical power generation, transient torque management, and shock load reduction. By integrating the over-running clutch into the rotor assembly, the system achieves these multiple functions without requiring separate external mechanisms, simplifying the overall manufacturing process while improving reliability.
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
This solution extends clutch life, reduces maintenance downtime, maintains generator output, and lowers construction costs while ensuring reliability under varying torque conditions.
Implementation Method 1
The rotating assembly differs from existing clutching devices by a presence of one or more friction elements that raise a torque threshold that is required to initiate relative motion between a shaft and a core of the rotating assembly
Implementation Method 2
the over-running shaft core assembly integrates an over-running capability directly within the rotating assembly to resolve issues due to transient torque loads
Data Source
AI summary
A rotating over-running shaft core assembly described herein decouples a clutching mechanism from load effects caused by an external belt driving an electrical machine. An integrated the clutch mechanism decouples stresses applied by the external belt to contend with radial loads associated with the mass of the rotor structure Friction elements integrated into the over-running shaft core assembly and positioned to provide a friction effect to the rotating shaft reduces shock loads that may be experienced at the shaft upon clutch engagement and re-engagement, such as when oscillating through an engine revolution range.