Electronic CVT
The goal of this project was to design and build a unique electronic CVT that could be used on a SAE Baja type vehicle. This design would respond to electronic signals to shift and move the sheaves on the pulleys changing the effective gear ratio. This change from a traditional mechanical CVT would allow for significantly easier tuning and testing as well as built in data collection for future design decisions.
Significant amounts of technical analysis were required in this project to ensure the final result would be able to shift adequately quickly and maintain the desired gear ratio. Most importantly the team had to find the required “clamping force” which is the force that needs to applied to the movable sheaves in order to transmit the torque from the sheave to the belt. This would lead to accurate motor sizing for the project.
This design used a unique screw driven concept that moved the sheave back and forth by spinning a acme threaded screw inside a nut attached to the sheaves. The design can be seen below, with the electronic motor mounting to the green plate, interfacing with the shaft adapter and eventually the screw mechanism.
