SAEⓇBaja - Brakes and Rear Suspension Kathryn Kempema

Overview Objectives Design Testing Failure Analysis Conclusions http://cnx.org/content/m42211/latest/?collection=col11406/latest

SAE BAJA 2015 Design Competition - Portland Oregon May 2015 Tasks include: Brake Test Lock up all 4 tires Endurance Race 4 hrs. rough terrain Hill Climb & Rock Crawl Photos courtesy of 2014 UWYO SAE Baja Team

Brakes - Objectives Rules: Hydraulically controlled brakes Hydraulic brake light switch Independent brake circuits (front and rear) Lock up all four tires on any surface Ours: Foot operated brake Improve bias adjustments between circuits Prevent brake drag http://www.formula1-dictionary.net/braking_tech.html

Brake Schematic

Brake Model Assumed inputs were brake pedal force and rotor coefficient of friction Model shows that car will lock up all 4 wheels regardless of operating surface

Braking Test The brakes generated 1200 psi line pressure in both lines for a 50:50 balance with no bias This is in the range of inputs which will ensure that the car can lock all 4 tires at once Maximum Pressure 1400 psig < 2600 psig Maximum Pressure for components in the system

Preventing brake drag Last year the brags dragged: To solve: Removed Gum from the O-rings in the Calipers Proper alignment of Caliper mounts Proper Alignment Incorrect Alignment

Financial Analysis Initial proposed budget: Brakes: $1,184.00* Actual spent: Brakes: $690.00 *Amounts budgeted were based on early cost estimates and included parts that were not purchased.

Conclusions Objective Met? Hydraulically Controlled Brakes* YES Hydraulic Brake Light Switch* Independent Brake Circuits* Lock up all 4 tires on any Surface* Improved bias adjustments TESTING REQUIRED Prevent brake drag * Objectives which we are required to meet by competition rules

Acknowledgments Sponsors UW Department of Mechanical Engineering Polaris Wilwood Shop Personnel Mike Schilt, Master Technician Korey Kreitman, Master Technician Vincent Dauer, Master Technician Advisors Dr. Robert G. Erickson Dr. Kevin Kilty Dr. Nancy Peck Dr. Paul A. Dellenback Group Members Jason Christensen Jesse Grosinger Seth Koertner

Expense Report Part Amount needed Cost per unit Master Cylinder 2 $90.00 Pedal Assembly 1 $177.00 Front Rotor $57.00 Brake Light Switch Pressure $14.00 Brake Line 20 ft. $40.00 Brake Line- Braided hose $47.00 Assorted Plumbing and Brake Fluid $50.00