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Downhill Mountain Bike Gearbox

Downhill Mountain Bike Gearbox. Josh Filgate, Jesse Kuhn, Morgan Misek Jay Seiter, Michael Witonis. Problem Statement. Problem Statement:

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Downhill Mountain Bike Gearbox

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  1. Downhill Mountain Bike Gearbox Josh Filgate, Jesse Kuhn, Morgan Misek Jay Seiter, Michael Witonis

  2. Problem Statement Problem Statement: When subjected to the abusive environment of downhill mountain biking, current drive train designs perform unreliably, require constant maintenance, and are easily damaged by a wide variety of external factors. Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  3. Proposed Solution Proposed Solution: To remedy these problems, it is our intention to design and construct an internal gearbox transmission. Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  4. Design Goals The final design will take into account: • Max rider input of 115 N-m at 90 RPMs • Existing gear ratios of current drive trains (2.1-3.3) • High impacts resulting from crashing • G-CON 2.0 mounting standards • Sealing against mud, snow, and dust • Industry standard shifters, cranks, and bottom brackets • Targeting racers accustomed to spending between $4000 and $7000 for a complete bike Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  5. Gearbox vs. Current Drive System UPDATE ME Gearboxes offer: • Ingress Protection • Separate sensitive surfaces from exposure to elements • Contain lubrication within a controlled environment • Impact Protection • Encloses potentially fragile components within a protective case • Low Maintenance • Less frequent lubrication and tuning required • Less repairs due to impacts • Improved Center of Gravity • Mass of shifting mechanisms (chain guide, derailleur, and cassette) moved to a lower and more central point in the frame • Improved handling Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  6. What is Downhill Mountain Biking? Downhill Races Involve: • High Speeds: • Up to 50+ mph • Natural Obstacles: • rock gardens • boulders • roots • steep terrain • Stunts: • drop-offs over 10 vertical ft • gap jumps of over 35 feet Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  7. Downhill Mountain Biking Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  8. Downhill Mountain Biking HIGH SPEEDS TRAIL DEBRIS LARGE OBSTACLES ROOTS & VEGETATION Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  9. Examples of Harsh Environments Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  10. Current Drive Train is Fragile IRREPAIRABLE FRAME AND COMPONENT DAMAGE EXPOSED DRIVE TRAIN COMPONENT FAILURE Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  11. State of the Industry: Market Research • Online Study: “How many Derailleurs did you break in 2007?” • 192 responses via forums on www.bustedspoke.com and www.ridemonkey.com • 47% of riders broke at least one derailleur in 2007 • 2 Pro riders broke more than 10 derailleurs Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  12. State of the Industry: Early Prototypes • First internal tranmission mountain bike prototypes introduced in the late 1990s • First bikes used existing technologies modified into centralized locations • Multi-speed hubs • Derailleur-in-a-box Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  13. Frame weldment Crank Input Bolt pattern State of the Industry: Future Growth • Creation of G-CON 2.0 standard • Growing number of frame manufacturers designing gearbox compatible frames • Interfacing between gearboxes and frames becoming more standardized Three current prototype designs that conform to the G-CON standards G-CON 2.0 Gearbox Interface Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  14. Brainstorming and Initial Concept Modeling Design Criteria Decision Matrix Proof of Concept Prototype Detailed System Design Design Process Phase 1: Shifting Mechanism Phase 2: Gear Assembly Phase 3: Case and Interfacing Concept Chosen for Design Step 1: Geometric Driven Modeling Step 2: Calculations performed on simplified geometries Step 3: Detailed Modeling Step 4: FEA with COSMOSWorks Iterative Analytical Design Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  15. Decision Matrix High Score Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  16. Brainstorming and Initial Concept Modeling Design Criteria Decision Matrix Proof of Concept Prototype Detailed System Design Design Process Phase 1: Shifting Mechanism Phase 2: Gear Assembly Phase 3: Case and Interfacing Concept Chosen for Design Step 1: Geometric Driven Modeling Step 2: Calculations performed on simplified geometries Step 3: Detailed Modeling Step 4: FEA with COSMOSWorks Iterative Analytical Design Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  17. PAWLS SHIFT BULB RETURN SPRING SHIFTING BULB PAWL RETURN SPRINGS SHIFT PULL CABLE Design Phase I: Shifting Mechanism Model of Current Shifting System Configuration Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  18. Design Phase I: Shifting Mechanism Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  19. Max Stress: 370 MPa Max Stress: 261 MPa Design Phase I: Shifting Mechanism Governing Equations: Cosmos FEA of Shaft and Pawl: τ = Tc ΣF = Σ ma = 0 J Assumptions: 2:1 Torque reduction from cranks to gearbox input Torque distributed evenly over the three pawls F.O.S. = 2 Simplified Geometry Calculations: Max stress calculated at outside diameter of shaft: 21.7 MPa Materials Selected: Shaft: 4130 Steel Q&T Pawl: 4130 Steel Normalized Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  20. Planetary Barrel Support Plate Barrel Bearing Hollow Drive Shaft Output Gear Sun Bearing Design Phase II: Gear Assembly Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  21. AGMA Bending Stress Buckingham Wear Load Fw = K Q b Dp Design Phase II: Gear Assembly • Three types of gear analysis performed • AGMA bending stress • Buckingham gear wear • Fatigue • Givens • Max rider input: 115 N-m at 90 RPMS • 2:1 Gear reduction from cranks to gearbox input • Product lifetime of 3 years • Independent Variables • Tooth width • Module • Pitch diameter • Material Governing Equations: Assumptions: K0 = 1.25 Kv = 1 Ks = 1 Km = 1.2 J = 0.35 F.O.S. = 1.25 Available Gear Materials: • 303 Stainless Steel • 416 Stainless Steel • l7-4 PH Stainless Steel • 2024 T4 Aluminum Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  22. Design Phase II: Gear Assembly Ring Gear Material Selected: 2024 T4 Aluminum Module: 1 Gear width: 5.6 mm Fatigue Stress Limit: 324 MPa Yield Strength: 325 Mpa AGMA Stress x F.O.S: 266 MPa Wear Stress: 19.9 MPa Sun Gear Material Selected: 416 Stainless Steel Module: 1 Gear width: 5.6 mm Endurance Limit: 277 Mpa Yield Strength: 277 MPa AGMA Stress x F.O.S: 266 MPa Wear Stress: 22.5 MPa Planet Gear Material Selected: 416 Stainless Steel Module: 1 Gear width: 5.6 mm Endurance Limit: 277 MPa Yield Strength: 277 MPa AGMA Stress x F.O.S: 266 MPa Wear Stress: 31.8 MPa Example of Gear Analysis: Gear Set 4 Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  23. Design Phase II: Gear Assembly Gear material was selected by optimizing AGMA bending stress and fatigue Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  24. .2*Fd .2*Fd .2*Fd Max Left Leg Loading Max Right Leg Loading .2*Fd Fd .2*Fd Design Phase III: Case and Interfacing Drive Shaft Bearing Support Support Flanges G-CON 2.0 Mounting Feature Barrel Bearing Support Output Shaft Bearing Support Threaded Bottom Bracket Shell • Mounts to G-CON 2.0 standard frames • Supports gears and shafts • Structural member of frame Free body diagram Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  25. Max Stress: 7 MPa Design Phase III Loading Conditions: Rider transmits 100% of load from vertical impact to pedals via legs 0% absorption with bike suspension Maximum force rider’s legs can transmit = 500 lb COSMOS FEA of Case: Material Selected: 6061 T6 Aluminum Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  26. Input Sprocket Shifting Cable Scalar Output Sprocket Gasket Industry Standard Bottom Bracket and Cranks Impact Resistant Bash Guard Design Phase III: Case and Interfacing Industry Standard Component Compatibility: • Shifting cable scalar interfaces with indexed shifters • Case sized and threaded for integration with standards bottom brackets and cranks • Standard mountain bike sprockets used for input and output Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  27. Final Design Weight:7.5 lbs Estimated Cost:$4000 Gear Ratios:2.1, 2.3, 2.5, 2.7, 2.9, 3.1, 3.3 Materials:416 Stainless Steel, 303 Stainless Steel, 17-4 PH Stainless Steel, 4130 Steel, 1045 Steel, 2024 Aluminum, 6061 Aluminum Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  28. Proof of Concept Prototype Weight: 8 lbs Cost:$1500 Gear Range:2.1, 2.5, 3.3 Materials:SLA, 303 Stainless Steel, 6061 Aluminum, 1045 Steel, Carbon Steel, Nylon Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  29. Concluding Thoughts • Proof of concept testing • Shifting mechanism functions • Gear configuration provides three distinct ratios • Case supports internal systems and interfaces with industry standard components • Sub systems mechanically integrate • Further development • Build and test final design prototype • Reduce weight • Extend lifetime • Improve manufacturability Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  30. Questions? Special thanks to the following individuals for their technical and moral support: Randy Moore, Brian Weinberg, Jim Forte Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  31. Extra Slides Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  32. Images Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  33. Images Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  34. - Face Width - Module - Material Yield Strength - Size Factor = 1 - Mounting Factor = 1.3 - Life Factor - Overload Factor = 1.5 (1 - 2.25) - Temperature Factor - Velocity Factor (precision, pitch velocity) - Reliability Factor - Transmitted tangential load - Geometry Factor: .45 AGMA Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  35. Different Suspensions with G-CON 2.0 ONLINE VIDEO OF MORE PIVOT DESIGNS Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  36. Slide Graveyard Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  37. Proof of Concept Prototype Final Design Prototype Weight:7.5 lbs Cost:$4000 Gear Ratios:2.1, 2.3, 2.5, 2.7, 2.9, 3.1, 3.3 Materials:416 Stainless Steel, 303 Stainless Steel, 17-4 PH Stainless Steel, 4130 Steel, 1045 Steel, 2024 Aluminum, 6061 Aluminum Proof of Concept Prototype Weight: 8 lbs Cost:$1500 Gear Range:2.1, 2.5, 3.3 Materials:SLA, 303 Stainless Steel, 6061 Aluminum, 1045 Steel, Carbon Steel, Nylon Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

  38. Final Design PLANETARY STACK SHIFTING CABLE SCALER INPUT SPROCKET OUTPUT SPROCKET STANDARD MOUNTAIN BIKE CRANKSET, BOTTOM BRACKET. AND BASHGUARD Design Team: Joshua Filgate, Jesse Kuhn, Morgan Misek, Jay Seiter, Michael Witonis

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