Baja SAE® Series 2015
February 11, 2015
Status Update
The Old Dominion University Baja Team is happy to report that we have almost completed the redesign of our two speed helical gearbox, which we originally started in Project Management MAE434W. The gearbox now incorporates a limited slip differential, purchased from American Honda Motor Company, Inc., which has been used in previous Old Dominion University Baja vehicles. Afterspeaking with Dr. Elmustafa and Kyle Gibson, the current leader of the Old Dominion University SAE Baja Club, about our goals for the new gearbox, we have chosen the following output ratios: 11.33:1 and 8.57:1. These ratios were picked based on the necessary torque and desired speed for previous SAE challenges such as hill climb, mud bog, and the endurance run. In our redesign of the gearbox, we have also changed the diametrical pitch, helix angle, as well as the pressure angle of all of our gear sets. Recently, our group has been in contact with two machinists from Mechanical Technologies, who are assisting as consultants in the design of the gearbox case. Starting next week we will begin an analytical finite element analysis of the gear sets in order to better determine their deformation under max loading and shock loading, while finalizingdesign work on the gearbox case design.
The suspension team has been working on designing the new rear suspension that will incorporate passive rear steering. Utilizing Solidworks, the team has been able to design a new swing arm that will mount to each side of the redesigned frame. The team used McMaster-Carr to select a steel ball joint rod end ½” – 20 RH Male Shank, 3/8” Ball ID, 1-3/8” Long Thread. Using the selected rod ends, the new mounts have been designed to make the appropriate connections with 3/8” steel bolts. The swing arm includes five mounting points; one to connect the shocks to the frame to absorb forces exerted on the rear wheels, two that will connect to the newly designed hub to mount the brake assembly and wheels, and finally two that will connect to the frame underneath the gearbox to allow passive steering. The team has successfully designed the swing arm, all five mounts, the rod ends, and the hub assembly. In the future weeks the suspension team will finalize the mounting locations to the frame, analytically testing for stress and strains, and make selections on bolts, bushings, and brake assemblies.