Ananth Kutuva - Electric Race Car

Olin Electric Motorsports is Olin College's Formula EV team that designs, builds, and races an electric race car in the Formula SAE Electric competition. It is my second year on the team, and I have designed and fabricated several parts for the car's powertrain, including the sprocket adaptor and eccentric tensioners.

As the Powertrain Subteam Lead this year, my role has been focused on revising MK.7's drivetrain for weight and cost savings, while ensuring reliable performance.

My role as a subteam member last year included designing and manufacturing the sprocket adaptor (red) and manufacturing the eccentric tensioners (blue).

Sprocket Adaptor

Essential for the transfer of torque through the drivetrain assembly, the sprocket adaptor connects the rear driven sprocket to the differential through a three-bolt interface.

Deformation FEA Plot

Modal Analysis FEA Plot

Factor of Safety FEA Plot

Lightweighting Material Removal FEA Plot

By performing both hand calculations and Finite Element Analysis (FEA), I was able to create a design that would withstand the loads coming through the chain and into the sprocket without the adaptor deforming or shearing under the load.

I used the peak stall torque output of our EMRAX 228 motor and its magnified effect on the sprocket teeth to get a worst-case scenario load through the adaptor clearance holes.

I used SolidWorks Static, Modal, and Topology FEA studies to further understand where I could save weight on the thick part and if the rotational frequency of the assembly would have a detrimental effect on the part.

The manufacturing process for the adaptor included turning the blank's three diameters down on the manual lathe till the waterjetted sprocket would fit on the adaptor with a near-press fit.

Talking to the shop staff, I realized I needed to machine a separate set of soft jaws to hold the adaptor in the Tormach CNC mill, so I modeled and CNC milled these jaws to hold the adaptor by its smallest diameter.

Once the adaptor was in place, I face-milled its top and the three-arm profile next. Using a series of tools such as the shear hog, 3/8" flat endmill, and 1/4" flat endmill, I was able to program the mill into the deep pockets to remove as much material as possible.

Eccentric Tensioners

These tensioners hold the rear differential in place, rotating to put tension on the chain, and are bolted in place with lock nuts. They allow us to precisely adjust the amount of slack in the chain without needing separate idler pullies or components to keep tension on the chain.

My role was focused on manufacturing these parts and ensuring a transition fit with the outer clockage plates and a press fit with the inner bearing bore.

The tensioners started as 6" x 6" aluminum stock, which I CNC machined and lathed down.