July 2025 - January 2026 (Projected) | Baja SAE
Currently designing internals for the transfer case gearbox for the 2025-2026 Northwestern Baja SAE car. The transfer case is a 1:1, 90 degree gearbox used to transmit power from the main gearbox to the prop shaft, enabling the car to use 4WD.
The transfer case for the 2024-25 car, the only one our team has made thus far, was very overdesigned. With this design, one of my main goals was to reduce the weight and size of the gearbox to only what is necessary.
Since our team doesn’t have the ability to custom-manufacture gears, I chose two commercially-available spiral bevel gears with a calculated factor of safety of 1.20. This maintains a good margin of safety while not forcing us to use larger, heavier gears.
So far, I have created a draft design of the shaft assemblies for both the input and output shafts. With this draft, I created a spreadsheet to automatically calculate factors of safety for the shafts and bearings as parameters like shaft material, components, and distances change in further design iterations.
Draft CAD of the input and output shaft assemblies.
Finalize shaft assembly and design
Conduct stress analysis on keyways and keys
This hasn't been done on any of our gearboxes in past years, but has been a relatively common point of failure
Select bearings
Manufacture the shafts and assemble!