This project was conducted for a gearbox design course at Queen's. The goal was to design a gearbox for a pre-built racing car that competed in two events: A top speed event and a hill-climb event. Throughout the project, I designed various components of the gearbox including the input/output shafts, casing, and contributed to the gear design. All parts for the gearbox were 3D printed.
Above can be seen the various components that made the gearbox design. The gears' pitch diameter and teeth number were determined through Python code iterations subject to the constraints of the project.
The gear design was conducted based on the two events the car raced in. Since both events require different gear ratios we decided on opting for a two-stage geartrain with one pairing dedicated for the speed event and the other for the hill climb event. For the former, the chosen gear reduction ratio was 0.6 and for the latter it was 2.24. Both of these were chosen based on the dimensional constraints of the gearbox in the pre-built car.
The case needed to fit specific dimensions in order to fit in the car. As such we conducted topology optimization in SolidWorks to determine how much material could be removed to reduce mass.
I conducted the design for the input and output shafts following the design of the gears. The inner diameter of each of the spur gears dictated the design of the shafts. Other components to note were the diameters where the shafts were placed in the bushing.
Input Shaft
The various diameters of the input shaft were to account for the different inner diameters of the gears, the necessary shoulders, and the bushing location.
Output Shaft
The same methodology and constraints used for the input shaft were reproduced for the output shaft this time accounting for the sister gears.
Speed Event: The speed event was conducted on a flat strip 3 meters in length. Our team achieved a podium being placed third in this event out of 60 teams competing.
Hill-Climb Event: The hill-climb event was done on a 45° curved ramp. For this particular event our car slightly underperformed but still placed in the top 15.