Developing a top-quality gearbox

Formula Electric Belgium (FEB) is a team of about 40 students in total who each year create an electric race car based on the latest and greenest technologies. The team was founded in 2010. Since then, the team has tried to climb up the Formula Student world ranking via participation in yearly competitions during the summer months. They started with a car with a steel-tube frame, no aero package and low efficiency that weighed 340 kg and had a 0-100 km/h acceleration of 4.1 s. Thirteen years later, their car has a carbon fiber monocoque, a sophisticated aero package, weighs 213 kg and has a sub 2.5 s acceleration. All these innovations were only possible because of close partnerships with a variety of companies.

The team participates in 3 to 4 competitions each year. The final leaderboard of these competitions is based on both dynamic (acceleration, skid pad, autocross and endurance) and static (cost analysis, design analysis and business plan) events. Besides competitions (technical work) they also have a lot of non-technical work, such as BR, PR, Recruitment and giving STEM-classes to secondary school students informing the new generation about the possibilities of science and engineering.

Developing a top-quality gearbox thanks to design software

Formula Electric Belgium (FEB) has been using KISSsoft® since 2017. KISSsoft has helped the team enormously in developing a state-of-the-art gearbox, which is able to perform under all different types of circumstances. Based on their positive experiences of the last few years, FEB wants to make the gearbox assembly for this year’s car more compact. The team makes use of a compound epicyclic gearbox. Normally, the so-called carrier is the output of this type of gearbox. But this year the layout will change, making the ring gear the output of the gearbox. This enhances the drivability of the car, the acceleration and the aerodynamic losses. For this innovation, they will again make use of this efficient software to thoroughly simulate and analyze the interaction of the gears. The possibilities in the field of strength calculations and contact analysis are extensive and determine the final design of our gearbox directly.

A new layout of the gearbox

This new layout of FEB’s gearbox is already thoroughly investigated in two master theses during the past two years. These theses give some clear examples on where KISSsoft helped the students solve certain problems. The biggest problem/challenge in a Formula Student car is the combination of a compact lightweight gearbox that is also strong enough for the severe conditions our car can suffer during competition. Here are a few findings on how KISSsoft helped tackle this challenge:

• Materials: Simulations can be easily performed using different kinds of materials and give us the best    material choice.
• Lifespan and load cases: Formula Student gearboxes are ‘special’ in the field of lifespan and load cases compared to for example normal family cars. KISSsoft makes it easy for us to analyze different load cases based on torsion and speed factors. The calculated lifespan is checked against the worst-case value. The different load cases are used to optimize the microgeometry of our gears.
• Configuration notifications: based on the center distances in the gearbox and the inner diameters of the gears given as input, KISSsoft gives error messages when certain configurations input are physically not feasible.
• Detail and possibilities (microgeometry of the gears): the deviation and inclination errors can also be input in full to perform in-depth contact analysis. These deviation and inclination errors are the starting point of our profile adjustments (microgeometry of the gears). For the profile adjustments, the members of the team use an iterative process to optimize the crowning, tip relief and/or root relief of the gears to again reach the desired lifespan and minimize weight.

With the support of partners such as KISSsoft AG, the FEB 2024 team is extremely motivated to further improve this year’s car design. For the Powertrain department, the new layout of the gearbox will be the most innovative aspect. KISSsoft provides the team with detailed gear simulations to reach this goal.