Overview

Designed a free-spinning rear wheel hub to replace one of the two rear motors in the MS15.5 solar car, reducing weight and improving energy efficiency.

Design Requirements

The rear wheel hub must retain the brake rotor and wheel rim positions from the previous motor-mounted version to maintain the vehicle's driving dynamics.

The design must maintain structural integrity under static, acceleration, and braking load conditions, meet the American Solar Challenge's 2x safety factor requirement, and minimize assembly weight.

Mechanical Design

The rear wheel hub assembly is composed of

• Spindle: Attached to the suspension trailing arm and holding the wheel hubs' bearings, allowing for rotation
• Wheel Hub: Rotates on the spindle and is connected to the wheel rim and the brake mounting plate.
• Break Rotor Attachment Plate: Connects the break rotor to the wheel hub.
• Wheel Rim

FEA Analysis

Conducted linear static FEA simulations on the spindle and wheel hub to validate structural integrity. Using SolidWorks FEA to simulate the static, acceleration, and breaking cases. Using the findings to identify areas for weight reduction and to manage local maximum stress.

Drawings

Created engineering drawings for the rear wheel hub assembly using ordinate dimensioning and GD&T, to communicate design intent and ensure manufacturability.

Results

Design reduced the assembly mass by 65% and improved performance at the FSGP 2025 competition.