Submitted by: Analysis Lead, Nick Jaegle

INTEGRIS’ engineers were presented the task to address failures encountered within an electromagnetic subsystem component serving as the clutch mechanism allowing selective power transmission to the other accessory systems. This subsystem is used in severe duty applications where reliability and predictable service life is crucial to staying profitable. The electromagnetic clutch had been experiencing a failure rate of over 5% on average. Initial attempts to reduce failures consisted of periodic tweaking of design and manufacturing parameters without a sound understanding of the system, resulting in the typical outcome of limited success and wasted dollars. We therefore suggested an Engineering Simulation and upon some rock solid clear and open communication (aka collaboration) with the customer they (the engineers) reviewed available design and field data, or lack thereof, determining that a torque overload condition was occurring stemming from an inadequate pull force produced from within the clutch. To make a long story short, the engineers determined a pull force increase of 15-20% will naturally eliminate these failures.

 

To solve the problem a combination of engineering know how, material property investigation, simulation and test were applied to start. The magnetic properties of several steel alloys used within the electromagnetic clutch were correlated via test. Those properties were then implemented within a finite element model of the clutch where performance was simulated and optimized. A typical input voltage was applied to the model. Flux lines and densities were analyzed and geometry was adjusted until the pull force output was maximized to improve overall clutch performance.

Results yielded:
• 45% increase in pull force output
• Predicted reduction of failure rates to
less than 1%
• No net weight increase
• No increase in heat production
• 50% Engineering Cost Reduction based
on previous development project data

 

For more information including the entire case study or to download a pdf copy of it please click here.