Post on 01-Feb-2016
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Downhill Mountain Bike Gearbox
Josh Filgate, Jesse Kuhn, Morgan MisekJosh Filgate, Jesse Kuhn, Morgan Misek
Jay Seiter, Michael WitonisJay Seiter, Michael Witonis
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
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.
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Proposed SolutionProposed Solution: To remedy these problems, it is our intention to design and construct an internal gearbox transmission.
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Design Goals The final design will take into account: The final design will take into account:
1.1. Max rider input of 115 N-m at 90 RPMsMax rider input of 115 N-m at 90 RPMs2.2. Existing gear ratios of current drive trains (2.1-3.3)Existing gear ratios of current drive trains (2.1-3.3)3.3. High impacts resulting from crashing High impacts resulting from crashing 4.4. G-CON 2.0 mounting standardsG-CON 2.0 mounting standards5.5. Sealing against mud, snow, and dustSealing against mud, snow, and dust6.6. Industry standard shifters, cranks, and bottom bracketsIndustry standard shifters, cranks, and bottom brackets7.7. Targeting racers accustomed to spending between $4000 Targeting racers accustomed to spending between $4000
and $7000 for a complete bikeand $7000 for a complete bike
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Gearbox vs. Current Drive System
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
UPDATE ME
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
Gearboxes offer:
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
What is Downhill Mountain Biking?
High Speeds:High Speeds: Up to 50+ mph
Natural Obstacles:Natural Obstacles: rock gardens boulders roots steep terrain
Stunts:Stunts: drop-offs over 10 vertical ft gap jumps of over 35 feet
Downhill Races Involve:Downhill Races Involve:
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Downhill Mountain Biking
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
HIGH SPEEDS
ROOTS & VEGETATION
TRAIL DEBRIS
LARGE OBSTACLES
Downhill Mountain Biking
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Examples of Harsh Environments
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Current Drive Train is Fragile
EXPOSED DRIVE TRAIN COMPONENT FAILURE
IRREPAIRABLE FRAME AND COMPONENT DAMAGE
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
State of the Industry: Market Research
Online Study: “How many Derailleurs did you Online Study: “How many Derailleurs did you break in 2007?”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
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
State of the Industry: Early Prototypes
First internal tranmission mountain bike prototypes introduced in First internal tranmission mountain bike prototypes introduced in the late 1990sthe late 1990s
First bikes used existing technologies modified into centralized First bikes used existing technologies modified into centralized locationslocations
Derailleur-in-a-box Multi-speed hubs
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
State of the Industry: Future Growth
Creation of G-CON 2.0 standardCreation of G-CON 2.0 standard Growing number of frame manufacturers Growing number of frame manufacturers
designing gearbox compatible framesdesigning gearbox compatible frames Interfacing between gearboxes and Interfacing between gearboxes and
frames becoming more standardizedframes becoming more standardized
Frame weldmentCrank Input
Bolt pattern
Three current prototype designs that conform to the G-CON standards
G-CON 2.0 Gearbox Interface
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Design Process
Phase 1: Shifting MechanismPhase 1: Shifting MechanismPhase 2: Gear AssemblyPhase 2: Gear AssemblyPhase 3: Case and InterfacingPhase 3: Case and Interfacing
Step 1: Geometric Driven ModelingStep 1: Geometric Driven Modeling
Step 2: Calculations performed on Step 2: Calculations performed on simplified geometriessimplified geometries
Step 3: Detailed ModelingStep 3: Detailed Modeling
Step 4: FEA with COSMOSWorksStep 4: FEA with COSMOSWorks
Brainstorming and Initial Concept Modeling
Design Criteria Decision Matrix
Detailed System DesignProof of Concept Prototype
Concept Chosen for Design
Iterative Analytical Design
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Decision Matrix
Conventional Conventional
SequentialSequential PlanetaryPlanetaryPlanetary Planetary
BarrelBarrelSequential Sequential SprocketsSprockets
Derailleur in a Derailleur in a boxbox
CriteriaCriteriaCriteria Criteria FactorFactor RatingRating ScoreScore RatingRating ScoreScore RatingRating ScoreScore RatingRating ScoreScore RatingRating ScoreScore
WeightWeight 55 22 1010 33 1515 44 2020 44 2020 44 2020
PackagingPackaging 55 44 2020 33 1515 55 2525 33 1515 22 1010
DurabilityDurability 55 55 2525 44 2020 55 2525 33 1515 22 1010
EfficiencyEfficiency 33 33 99 33 99 33 99 55 1515 55 1515
InterfacingInterfacing 44 22 88 44 1616 33 1212 33 1212 55 2020
Shifting feelShifting feel 44 55 2020 33 1212 33 1212 44 1616 22 88
Total Total Score:Score: 9292 8787 103103 9393 8383
High Score
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Design Process
Phase 1: Shifting MechanismPhase 1: Shifting MechanismPhase 2: Gear AssemblyPhase 2: Gear AssemblyPhase 3: Case and InterfacingPhase 3: Case and Interfacing
Step 1: Geometric Driven ModelingStep 1: Geometric Driven Modeling
Step 2: Calculations performed on Step 2: Calculations performed on simplified geometriessimplified geometries
Step 3: Detailed ModelingStep 3: Detailed Modeling
Step 4: FEA with COSMOSWorksStep 4: FEA with COSMOSWorks
Brainstorming and Initial Concept Modeling
Design Criteria Decision Matrix
Detailed System DesignProof of Concept Prototype
Concept Chosen for Design
Iterative Analytical Design
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Design Phase I: Shifting Mechanism
Model of Current Shifting System Configuration
SHIFTING BULB
PAWL RETURN SPRINGS
PAWLS
SHIFT BULB RETURN SPRING
SHIFT PULL CABLE
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Design Phase I: Shifting Mechanism
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Design Phase I: Shifting Mechanism
Governing Equations:
Assumptions:
Materials Selected:
Shaft: 4130 Steel Q&T
Pawl: 4130 Steel Normalized
τ = TcJ
ΣF = Σ ma = 0
2:1 Torque reduction from cranks to gearbox input
Torque distributed evenly over the three pawls
F.O.S. = 2
Cosmos FEA of Shaft and Pawl:
Max Stress: 370 MPa
Max Stress: 261 MPa Simplified Geometry Calculations:
Max stress calculated at outside diameter of shaft: 21.7 MPa
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Design Phase II: Gear Assembly
Planetary Barrel
Hollow Drive Shaft
Output Gear
Support Plate
Sun Bearing
Barrel Bearing
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Design Phase II: Gear Assembly Three types of gear analysis performedThree types of gear analysis performed
AGMA bending stress Buckingham gear wear Fatigue
GivensGivens Max rider input: 115 N-m at 90 RPMS 2:1 Gear reduction from cranks to gearbox input Product lifetime of 3 years
Independent VariablesIndependent Variables Tooth width Module Pitch diameter Material
J
KK
bmKKF ms
vt
0.10
AGMA Bending
Stress
Fw = K Q b Dp Buckingham Wear Load
Governing Equations:
Assumptions:K0 = 1.25
Kv = 1
Ks = 1
Km = 1.2
J = 0.35
F.O.S. = 1.25
Available Gear Materials:
l7-4 PH Stainless Steel
2024 T4 Aluminum
303 Stainless Steel
416 Stainless Steel
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Design Phase II: Gear Assembly
Ring GearRing Gear
Material Selected: Material Selected: 2024 T4 Aluminum
Module: 1 Gear width: Module: 1 Gear width: 5.6 mm
Fatigue Stress Limit: Fatigue Stress Limit: 324 MPa
Yield Strength: Yield Strength: 325 Mpa
AGMA Stress x F.O.S: AGMA Stress x F.O.S: 266 MPa
Wear Stress: Wear Stress: 19.9 MPa
Planet GearPlanet Gear
Material Selected: Material Selected: 416 Stainless Steel
Module: 1 Gear width: Module: 1 Gear width: 5.6 mm
Endurance Limit: Endurance Limit: 277 MPa
Yield Strength:Yield Strength: 277 MPa
AGMA Stress x F.O.S: AGMA Stress x F.O.S: 266 MPa
Wear Stress: Wear Stress: 31.8 MPa
Sun GearSun Gear
Material Selected: Material Selected: 416 Stainless Steel
Module: 1 Gear width: 5.6 mmModule: 1 Gear width: 5.6 mm
Endurance Limit: Endurance Limit: 277 Mpa
Yield Strength:Yield Strength: 277 MPa
AGMA Stress x F.O.S: AGMA Stress x F.O.S: 266 MPa
Wear Stress: Wear Stress: 22.5 MPa
Example of Gear Analysis: Gear Set 4Example of Gear Analysis: Gear Set 4
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Design Phase II: Gear Assembly
Gear material was selected by optimizing AGMA bending stress Gear material was selected by optimizing AGMA bending stress and fatigueand fatigue
AGMA Fatigue AGMA Fatigue AGMA Fatigue AGMA Fatigue
Set 1
Selected Material2024 Aluminum 303 Stainless Steel 416 Stainless Steel 17-4 PH Stainless Steel
Planet N N N N N N Y Y 17-4 PH Stainless SteelSun N N N N N N Y Y 17-4 PH Stainless SteelRing N N N N N N Y Y 17-4 PH Stainless SteelSet
1
Set 2
Planet Y N Y N Y N Y Y 17-4 PH Stainless SteelSun Y N N N N N Y Y 17-4 PH Stainless SteelRing Y Y N N N N Y Y 2024 AluminumSet
2
Set 3
Planet Y N Y N Y Y Y Y 416 Stainless SteelSun Y N Y N Y Y Y Y 416 Stainless SteelRing Y Y Y N Y Y Y Y 2024 AluminumSet
3
Set 4
Planet Y N Y N Y Y Y Y 416 Stainless SteelSun Y N Y N Y Y Y Y 416 Stainless SteelRing Y Y Y N Y Y Y Y 2024 AluminumSet
4
Set 5
Planet Y N Y Y Y Y Y Y 416 Stainless SteelSun Y N Y Y Y Y Y Y 303 Stainless SteelRing Y Y Y Y Y Y Y Y 2024 AluminumSet
5
Set 6
Planet Y N Y Y Y Y Y Y 303 Stainless SteelSun Y N Y Y Y Y Y Y 303 Stainless SteelRing Y Y Y Y Y Y Y Y 2024 Aluminum
Set 7
Set 6
Planet Y N Y Y Y Y Y Y 303 Stainless SteelSun Y N Y Y Y Y Y Y 303 Stainless SteelRing Y Y Y Y Y Y Y Y 2024 AluminumOutput Y Y N N Y N Y Y 2024 Aluminum
Set 7
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Design Phase III: Case and Interfacing
Mounts to G-CON 2.0 standard Mounts to G-CON 2.0 standard framesframes
Supports gears and shaftsSupports gears and shafts Structural member of frameStructural member of frame
Max Left Leg
Loading
Max Right Leg
LoadingFd
.2*Fd
.2*Fd
.2*Fd
.2*Fd
.2*Fd
Threaded Bottom Bracket Shell
Barrel Bearing Support
Support Flanges
Output Shaft Bearing Support
G-CON 2.0 Mounting Feature
Drive Shaft Bearing Support
Free body diagram
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Design Phase III
Loading Conditions: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
Material Selected:Material Selected:
6061 T6 Aluminum
COSMOS FEA of Case:COSMOS FEA of Case:
Max Stress: 7 MPa
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Design Phase III: Case and Interfacing
Shifting Cable Scalar
Industry Standard Bottom
Bracket and Cranks
Gasket
Impact Resistant Bash
Guard
Input Sprocket
Output Sprocket
Industry Standard Component Compatibility: Industry Standard Component Compatibility: Shifting cable scalar interfaces with indexed shiftersShifting cable scalar interfaces with indexed shifters Case sized and threaded for integration with standards bottom brackets and cranksCase sized and threaded for integration with standards bottom brackets and cranks Standard mountain bike sprockets used for input and outputStandard mountain bike sprockets used for input and output
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Final Design
Weight:Weight: 7.5 lbs
Estimated Cost:Estimated Cost: $4000
Gear Ratios:Gear Ratios: 2.1, 2.3, 2.5, 2.7, 2.9, 3.1, 3.3
Materials:Materials: 416 Stainless Steel, 303 Stainless Steel, 17-4 PH Stainless Steel, 4130 Steel, 1045 Steel, 2024 Aluminum, 6061 Aluminum
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Proof of Concept Prototype
Weight: Weight: 8 lbs
Cost:Cost: $1500
Gear Range:Gear Range: 2.1, 2.5, 3.3
Materials:Materials: SLA, 303 Stainless Steel, 6061 Aluminum, 1045 Steel, Carbon Steel, Nylon
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Concluding Thoughts
Proof of concept testingProof 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 developmentFurther development Build and test final design prototype Reduce weight Extend lifetime Improve manufacturability
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Questions?
Special thanks to the following individuals for their technical and moral support:
Randy Moore, Brian Weinberg, Jim Forte
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Extra Slides
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Images
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Images
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
b - Face Width
m - Module
sK - Size Factor = 1
mK - Mounting Factor = 1.3
0K - Overload Factor = 1.5 (1 - 2.25)
vK - Velocity Factor (precision, pitch velocity)
tF- Transmitted tangential load
J - Geometry Factor: .45
RT
Ltall KK
KS
AGMA
tS - Material Yield Strength
LK - Life Factor
TK - Temperature Factor
RK - Reliability Factor
J
KK
bmKKF ms
vt
0.10
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Different Suspensions with G-CON 2.0
ONLINE VIDEO OF MORE PIVOT DESIGNS
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Slide Graveyard
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Proof of Concept Prototype
Final Design Prototype
Weight:Weight: 7.5 lbs
Cost:Cost: $4000
Gear Ratios:Gear Ratios: 2.1, 2.3, 2.5, 2.7, 2.9, 3.1, 3.3
Materials: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: Weight: 8 lbs
Cost:Cost: $1500
Gear Range:Gear Range: 2.1, 2.5, 3.3
Materials:Materials: SLA, 303 Stainless Steel, 6061 Aluminum, 1045 Steel, Carbon Steel, Nylon
December 4th, 2007Design Team: Joshua Filgate, Jesse Kuhn,
Morgan Misek, Jay Seiter, Michael Witonis
Final Design
PLANETARY STACK
INPUT SPROCKET
STANDARD MOUNTAIN BIKE CRANKSET, BOTTOM BRACKET. AND
BASHGUARD
SHIFTING CABLE SCALER
OUTPUT SPROCKET