CalPoly: designing the drivetrain

In late 2018, Eric and Marco decided to sponsor a California Polytechnic State University senior design team to help them research, design, manufacture, and test a subsystem of their project. Starting January 2019, mechanical engineering students Kai Liu, Carsten Frauenheim, Shelby Lampshire, and Isabel Skene began extensive research into patents, train car design, railway standards, and drivetrain options.

Fig 1: drivetrain assembly

Fig 2: 3D rendering

The process became iterative, and discussions with Eric, Marco, and their Cal Poly project mentor led to many varied design options. Once a design direction was approved, the team decided on a final version! Featuring a fixed axle supported by two V-shaped arms mounted to a solid support structure, the final design allowed for heavy loads, repeatable manufacturing, and overall modularity. The design can be adapted for various track gauges, various motor sizes, and can be mounted at any point along the rail car, with or without suspension components.

Fig 3: FEA mechanical stress analysis

An HPEV AC-20 electric motor was mounted to the upper support structure, chain-driving the axle at a 3:1 drive ratio. Failure analysis and Finite Element Analysis (FEA) were performed on the arms and support structure. Once the design was approved, manufacturing was free to begin!

- Carsten