Free Hub Test Machine Project # 34 Final Design Report 6/12/14 Sponsor: Specialized Bicycle Components Inc. Contact: Marshall Poland Brett Murphy [email protected] Mitch Ambrosini [email protected] Nick Boldt [email protected] Stephen Knaus [email protected] 2 Statement of Disclaimer Since this project is a result of a class assignment, it has been graded and accepted as fulfillment of the course requirements. Acceptance does not imply technical accuracy or reliability. Any use of information in this report is done at the risk of the user. These risks may include catastrophic failure of the device or infringement of patent or copyright laws. California Polytechnic State University at San Luis Obispo and its staff cannot be held liable for any use or misuse of the project. Table of Contents Statement of Disclaimer ............................................................................................................................... 2 List of Tables ................................................................................................................................................. 5 List of Figures ................................................................................................................................................ 5 Executive Summary ....................................................................................................................................... 7 Chapter 1: Introduction ................................................................................................................................ 7 Sponsor Background and Needs ............................................................................................................... 7 Formal Problem Definition ........................................................................................................................ 7 Objectives ................................................................................................................................................. 8 Project Management ................................................................................................................................ 9 Team Members ..................................................................................................................................... 9 Chapter 2: Background ............................................................................................................................... 10 Existing Products ..................................................................................................................................... 10 Current State of the Art .......................................................................................................................... 13 How a freehub Works ............................................................................................................................. 13 Specific Technical Data ........................................................................................................................... 16 Rear Wheel Loading ............................................................................................................................ 16 Definition of Failure ............................................................................................................................ 18 Compatibility ....................................................................................................................................... 18 Pedaling Test ....................................................................................................................................... 19 Freewheeling Test ............................................................................................................................... 20 Chapter 3: Design Development ................................................................................................................. 20 Conceptual Designs ................................................................................................................................. 21 Concept #1 .......................................................................................................................................... 21 Concept #2 .......................................................................................................................................... 22 Final Conceptual Design ...................................................................................................................... 23 Concept Selection ................................................................................................................................... 24 Prototype ................................................................................................................................................ 26 Chapter 4: Final Design ............................................................................................................................... 27 Overall Design Description ...................................................................................................................... 27 Detailed Design ....................................................................................................................................... 29 Tensioner and Motor Assembly .......................................................................................................... 29 4 Positioner and Brake ........................................................................................................................... 31 Frame .................................................................................................................................................. 32 Environmental Factors ........................................................................................................................ 34 Dropouts ............................................................................................................................................. 36 Control System .................................................................................................................................... 37 Pneumatic Lever Arm .......................................................................................................................... 40 Analysis Results ....................................................................................................................................... 41 Cost Analysis ........................................................................................................................................... 43 Material Selection ................................................................................................................................... 43 Geometry ................................................................................................................................................ 44 Component Selection .............................................................................................................................. 44 Electrical Systems .................................................................................................................................... 44 Safety ...................................................................................................................................................... 45 Maintenance and repair considerations ................................................................................................. 45 Chapter 5: Product Fabrication ................................................................................................................... 46 Description of manufacturing processes ................................................................................................ 46 Simplified Prototype ............................................................................................................................... 51 Recommendations for the future ........................................................................................................... 52 Chapter 6: Design Verification .................................................................................................................... 52 Test Description ...................................................................................................................................... 53 Detailed Results ...................................................................................................................................... 54 Project Phases and Milestones ............................................................................................................... 54 Conclusion and Recommendation .............................................................................................................. 55 Appendix A: QFD Analysis ........................................................................................................................... 57 Appendix B: Objectives Table .................................................................................................................... 58 Appendix C: Gant Chart............................................................................................................................... 59 Appendix D: EES Friction Calculation .......................................................................................................... 61 Appendix E: Design