Summary
Date: November 30, 2006
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Table of Contents |
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Report Summary Page |
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| Author: Daniel Hurst | Team: Uberboard |
Problem Statement
The Überboard is comprised of a steering, suspension, and braking system. The purpose for these systems is to allow the rider to have the most stable ride possible at high speeds while maintaining control of the Überboard. Slowing and stopping via the braking system is the topic of this design analysis. Specifically, the method in which the brakes interact with the wheels will be explored.
The Überboard is designed to approach very fast speeds. As the speeds become faster, stability and safety become a larger problem. The braking system will allow the rider to better control the speed and make the board more stable.
This report will explore this aspect of the braking system by cycling through the design development, which includes requirement and specification setting, benchmarking and brainstorming, concept sketches, design selection, design refinement, and final design selection.
Requirements & Specifications
Requirements
- Need to be applied evenly.
- Must not eject the rider if the brakes are on.
- Must be able to effectively stop the skateboard within a few seconds.
- Must be lightweight
- Need to take up as little space underneath the board as possible.
- Must wear evenly.
Specifications
- Applied braking pressure will need to be about 22 psi. See appendix for calculations.
- The board can decelerate from 15 mph to 0 mph in 10–15 seconds.
- The brake should take up no more than 3 cubic inches.
Concept Generation
Benchmarking of similar brake designs were done. These designs were the disc brake and the bicycle v brake. Both are used on bicycles and are likely candidates to achieve the requirements and specifications.
Seven different ideas were brainstormed using the mind map method. Many of the concepts utilize friction forces to slow the skateboard wheel down. Two of these seven concepts will be selected and refined in the next section.
Design Selection and Refinement
Design Selection
By using a design matrix for the seven generated concepts, two concepts will be further refined. Design matrices are shown in the Design Selection and Refinement and the Final Selection and Conclusion sections. The two designs that were chosen to be refined are the piston brake concept and the disc brake concept.
Piston Brake
Figure 2. Piston brake concept
A solid model is shown in Figure 2. In this design the piston is attached to the arm with brackets so that the brake pad is perpendicular to the wheel. The piston brake can be described as a crude disc brake. The wheel functions as the rotor and the hydraulically activated piston will add pressure to the wheel. This action will slow the wheel rotation and stop it. With using the wheel as a rotor, the wheels will wear down very quickly.
Disc Brake
Figure 3. Section view of disc brake
The second concept is a miniaturized disc brake. A sectioned model is shown in Figure 3. This design would be great for a skateboard. The disc brake will have two main components. They are a rotor connected to the wheel and a caliper with a small piston. The rotor connects to the wheel through a hollow shaft. This allows the wheel and rotor to spin together. When the rider activates the brakes a small piston will stop the rotor from spinning which in turn will stop the skateboard wheel.
Final Selection & Conclusion
Figure 4. Final disc brake design
The final design selected is the disc brake design. This design will allow the rider to safely stop or slow down when braking is required. Ejection from the Überboard will be unlikely because disc brakes will be located on all four wheels. The brake will be controlled using hydraulic fluid. This fluid controls the distance the piston moves and will allow for smooth, controlled braking. The disc brake design will take up much less space than the piston design and it will not wear the wheel out as quickly. Further testing and prototypes will be made to ensure that the design will work. This design will need to be adapted for the shape of the steering arm which has not been finalized as of yet. This is a minor detail and the brake can be easily adapted.
All solid models were created using ProEngineer Wildfire 3.0. Design matrix adapted from Dr. Provancher. Other images are referenced in text.
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