Next up in our Showcasing Series we have the Front and Rear Hubs!
Name: Finlay MacNeill
Sub-Team: Unsprung Mass
Parts: Front and Rear Wheel Hubs
What is the purpose of the components? The wheel hubs are designed to safely connect the wheels of the car to the rest of the unsprung mass assembly and because of this, the rest of the car. The front hubs do just this, whereas the rear hubs have an extra function of transferring the power from the drivetrain and engine into the wheels.
What are the specific features of your design? This year myself and the rest of the USM team made the decision to use different sized wheel bearings at the front and rear. Because we had chosen smaller front bearings this meant we could reduce the size of the front hub axle and reduce its weight significantly when compared to previous designs.
There is a lip feature on both the front and rear hubs that acts as a centering spigot for our wheel so that when the wheels are assembled onto the hubs, the important act of centering the wheel is done by this lip feature, rather than the wheel studs.
Ease of assembly was very important to the team for this year’s hubs and I decided to incorporate a stepped axle into the hub design so that when it came to pressing the hubs into the wheel bearings, there wouldn’t be any unwanted pushing or pulling on unsupported bearing faces that could potentially lead to damage.
Weight saving was also very important for this year’s USM team, especially with our change down to 10” wheels. To ensure that the hubs were as light as possible I introduced some very nice weight saving pockets into both the front and rear hubs. This was done by simulating the hubs using ABAQUS FEA and iteratively deciding where material was at its lowest stress and removing this from the final design.
This photo below is an example of the sort of simulation I was undertaking to remove material.
How did you test the parts? As shown above, the main bulk of the testing and validation for the wheel hubs comes from the FEA conducted during the design stage. There are initial simulations that I completed to see where material could be taken out of the hub designs and then closer to the end of the process, final simulations were completed to see what sort of factor of safety and fatigue life my designs had and if they were adequate enough for the team.
What were the challenges to overcome? The main challenges that I faced when designing these front and rear hubs were mainly down to complexity of working within one of our larger subassemblies on the car. Since we were moving down to 10” wheels this year it required a complete re-design of the USM assembly and that involved a lot of time and effort from everyone in the sub-team to make sure that our parts all worked together seamlessly and prevent any problems with contacting parts, assembly difficulties etc. Thankfully we have a very strong USM team this year and through a lot of double and triple checking as well as countless meetings, we manged to prevent any major problems from arising.
What are the main improvements from last year? The main improvements from this year’s hub designs must be the weight saving. I did manage to reduce the number of components in the hub assembly as well as make them slighter easier to fit together, but with this year’s hub assembly being 30% lighter than the previous one I feel very pleased with that result. That 30% along with the other weight savings in our wheels, brakes and uprights meant that the USM sub-team have saved our car approximately 15 kg for UGR-19!
Final thoughts? I would like to thank Hague fasteners for their outstanding job on the wheel studs for this years’ 2019 hub assembly, the money saved on purchasing these components as well as the strength and security they provide is invaluable, and we are incredibly pleased to have them onboard as part of the UGR-19 team!