Main objectives:

• Create a detailed electromagnetic FEA model in Ansys Maxwell to perform design optimization and performance simulations

• Develop the mechanical design of the magnetic gear

  • This was particularly challenging because the of the shape and size of the ferromagnetic piece rotor (the flux angle “mappers”)

• 3D print parts for the housing, support structures, and other pieces

• Iterate on the mechanical design

• Characterize the performance under via dynamometer tests and compare to FEA to validate the EM model

Challenges (ongoing so no results section):

• The outer bridge dilema:

  • The ferromagnetic pieces rotor (FP rotor) consists of 91 flux angle “mappers”, each is a different size and shape. To get the lamination stack manufactured, a thin “bridge” was added to outside diameter to hold all the FPs together

  • The bridge successfully made the laminations manufacturable, however it significantly decreases the maximum torque of the gear box since it shorts out the magnetic flux from the magnets, so it must be removed

  • This creates the challenge of “suspending” the FPs between the rotor magnets. The gap between the rotors and the magnets is only 1mm on each side.

Potential solutions:

• Injection molding

  • Would mold the whole FP rotor in some kind of plastic and then machine away the bridge

  • Issue is the very high initial cost of injection molding

• 3D printing

  • As pictured, create “fingers” that would fill the negative space between the FPs and hold them in place. Again the bridge would be machined away after all the pieces are held.

  • Issue was the rigidity of the 3D printed parts was low and accurately getting a press fit between the fingers and the FPs was difficult

• Resin/epoxy casting

  • Create a mold for the FP rotor and then cast the whole thing in epoxy resin to hold everything in place, and as with the other methods, machine the bridge away

  • First attempt failed on the last pass of machining due to the tool getting slightly caught on a protrusion on the inner diameter

  • Second attempt in progress with a different machining order and reinforced parts

A much more detailed explanation and analysis of the FAM concept can be found in my research paper. The paper can be accessed via IEEE Xplore or directly. The paper that has the prototype results and FEA model validation is currently a work in progress.