Capstone 2003

1
Capstone 2003

• Off-Roading Unlimited
• Presents
• The Marauder

2
Introduction to the Group(not presenting tonight)



Jason Sweeney
Britt Pratt
Rick Trushel
Bob Young

Brian Krall
Jeb Schreiber
Paul Vladuchick
Matt Brown

3
Presentation Overview

• Introduction
• Design Description
• Plant Layout
• Economic Analysis
• Testing Evaluation
• Conclusion
• Questions

4
Team Structure

• Frame Group
• Frame Assembly
• Suspension System
• Steering System

• Drivetrain Group
• Gearbox Assembly
• Braking System
• Rear Drive Components

5
The Marauder
6
Corporate Identity

• Principle Products and Product Lines
• Single seat, four-wheeled, recreational,
  off-road vehicle
• Full line of replacement parts

7
Corporate Identity

• Customer Base
• 16-29 year old males
• Off-road enthusiasts
• Persons living in rural areas
• Local off-roading outfitters

A typical customer type guy. Note the baseball
cap and the look that says, Im a 16 29 year
old male.

• Principal Markets
• ATV / dirt bike shops
• Purchasing or rental
• Track owners

8
SAE Mid-West Mini-Baja

• SAE student members with a challenging project
• Competing against 142 other collegiate teams
• All vehicles are powered by same engine
• No engine modifications means more competition

9
Design DescriptionFrame, Suspension, Steering
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Frame Assembly Goals

• 100 lbs weight
• Large Opening for entry and exit
• SAE requires 5 second exit time
• Allows for attachment of other components
• Factor of Safety (yielding) of 2
• Determined from 4 foot drop test
• Capable of carrying a 62 220 lb person

11
Frame Assembly Our Design

• Based on Finite Element Models and SAE rules
• 70 of frame was specified by SAE
• Materials
• 4130 Steel Tubing
• TIG welded

12
Frame Assembly Manufacture

• Cut and notched tubing
• Fit member into jig (if necessary, bend) and weld
• Test welded joints
• Sand and Paint

13
Frame Assembly Design Changes

• Added gusset plates to reduce stresses
• Moved / changed some members due to suspension
  changes
• Steering Column support added

Spring Semester
Fall Semester
14
Problems We Have Had

• Fitting and welding angled members
• Welding thin walled tubing
• Maintaining tolerances
• Tool life

15
Meeting Our Goals

• 110 lb frame
• Large Opening for easy entry and exit
• All components attached fairly easily
• Carried a 62, 220 lb person without breaking

16
Suspension System Design Goals

• 6 10 inches of travel
• 2 inches of compression when driver is seated
• Protect the frame from taking a beating from the
  terrain and make the ride more comfortable for
  driver
• 10-14 inches of ground clearance

17
Suspension SystemOur Design - Front

• Independent Dual Arm
• Bottom Shock Mount
• Wishbone design
• Consistency in manufacturing
• 17.5 inch shock absorbers
• 10 inches of ground clearance

18
Suspension SystemOur Design - Rear

• Independent Dual Arm
• Bottom Shock Mount
• Non-symmetric design to accommodate the half
  shafts and shock absorber
• 17.5 inch shock absorbers
• 9 inches of ground clearance

Top Arm Bottom Arm
19
Suspension System Design Changes

• Rear suspension shock mount from top to bottom
  arm

20
Suspension System Design Changes

• Control arms redesigned to accommodate the
  half-shafts and shock absorbers

Old Top Old Bottom
New Top New Bottom
21
Suspension System Manufacturing

• Tubing cut, bent and notched
• Placed in fixture and welded
• Bushings for attachment to frame

22
Suspension SystemProblems that we had

• Aligning the bushing surfaces on the arms
• Aligning the tabs on the knuckles between
  suspension arms

23
Meeting Our Goals

• 9 inches of travel front and back
• 2.5 inches of compression when driver enters
• Protects the Frame
• Articulation is not a problem
• Shocks soften loads before the maximum
  compression is reached

24
Design GoalsSteering System and Front Wheel
Assembly

• Minimal Driver Input
• Absolutely NO Bump Steer
• 7 foot maximum turning radius
• 1 turn lock to lock
• Simple design

25
Our Design Steering System

• Rack and Pinion
• Cast Aluminum Front Hubs
• Cast Steel Front Knuckle

26
Steering System Castings

• Designed using Pro/Engineer
• Pattern machined in house
• Cast out of house
• Secondary machining done in house

27
Steering System Front Hub

• Aluminum 319
• Attaches wheel to spindle
• Mounting point for brake rotors
• Spins freely on bearings

28
Steering System Front Knuckle

• Steel 1018
• Connects Front suspension control arms
• Facilitates steering
• Secures spindle in place
• Failed in testing

29
Steering System Assembly
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Meeting our Goals

• No bump steer at any speed
• Easy to turn at any speed
• 6 foot turning radius at any speed
• 1 turn lock to lock

31
Design Description Powertrain

• Engine, Transmission, Drivetrain, Braking

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Drivetrain Group

33
Marauder Drivetrain
34
How it Fits Together
35
CVT and Cover System

• Comet Model 790 CVT
• Speed Ranges
• Low end 3.381
• High end 0.541
• Cover required by SAE for protection

36
Gearbox

• Aluminum Cast Housing
• Sand Cast
• Machined in house
• Reduction of fasteners for production
• 9.41 Reduction
• Kinematic Top Speed 46 mph
• Kinematic Low Speed 3.6 mph

37
Gearbox

• Shafts
• Factor of safety of 2 against fatigue
• 4140 Steel 270 BHN
• Bearings
• Deep-Groove Single-Row Radial-Contact
• 90 Reliability

38
Gears

• Spur Gears
• Larger Heavier
• Helical Gears
• Smaller Lighter

Spur Gear
Helical Gears
39
Design Changes

• Gear cuts changed to radial holes
• Changes made to save cost
• Not as much weight reduction, 30 instead of
  40
• Production vehicle will have spur instead of
  helical gears

Changed from this
To this
40
Design Changes

• Keyways added to three of the four gears
• Change made per gear manufacturers advise
• One gear too small to add keyway
• Press fit retained on all surfaces for strength

41
A Closer Look at the Gearbox
42
Mounting System
43
Mounting System Changes

• Tab added to frame for support in rear
• Additional piece welded on for attachment to
  gearbox

44
Rear Drive Components

• U-Joint/Half-Shafts
• Spindle
• Hub
• Rear Wheels
• Knuckle

45
Rear Drive Components

• Aluminum Cast Rear Hub
• Steel Cast Rear Knuckle
• Spindle

46
Rear Wheel Assembly
47
Braking System

• 4-wheel hydraulic disc brakes
• Outboard in the front
• Single master cylinder
• Inboard in the rear
• Proportioning valve
• Stops in 35 feet from top speed

48
Assembly to Vehicle
49
Pedal Assembly

• Gas Cable
• Brake Master Cylinder
• Switch for Brake Light

50
Drivetrain Summary

• 10 hp Briggs and Stratton Engine
• Continuously Variable Transmission
• 2-Stage Helical Gear Reduction
• Top Speed 38 mph
• Total drivetrain weight of 110 lbs
• Hydraulic Disc Brakes
• Stops within 35 ft. from top speed
• Rear wheel components effectively transfer
  power from gearbox to wheels

51
Manufacturing Plant Layout
52
Production of the Marauder

• Production Quantity Varies over life of project
• Minimum Production Quantity of 2000 vehicles
  first year
• Peak Production Quantity of 4500 vehicles per
  year
• Cycle 10 hours per car

53
Production of the Marauder
54
Production Plans

• 20,000 square foot facility
• 2 8-hour shifts per day

• Staffed By
• 14 Machinists
• 18 Assemblers

55
Plant Layout
56
Economic Analysis
Yes, we ARE going to make money!
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Purpose of Economic Analysis

• Predict the fiscal performance of the company
• Locate areas of potential lower costs
• Determine rate of return
• Minimum Attractive Rate of Return 10
• Project Life Span 10 years

58
Expenses
59
Ways to Reduce Cost

• Value Engineering Finding components or
  subassemblies that can be simplified, eliminated,
  or produced with a cheaper manufacturing process.
• Gears helical to spur
• 400/vehicle savings
• Rack and pinion cover 3 bent sheet metal
  pieces, riveted together changed to 1
  thermoformed plastic piece.
• 10/vehicle savings

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REVENUE!!!
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Rate of Return

• Optimistic
• Expected
• Pessimistic

• 17.3
• 13.7
• 9.4

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Conclusion
Expected rate of return of 13.7 is higher than
the minimum attractive rate of return of 10
A typical banker-type guy. Notice the big
bankers goggles and the smile that says, I love
a rate of return of 13.7
63
Testing and Evaluation
64
Foundation

• Product Definition Statement
• SAE Mini-Baja Competition Rules
• Final Design
• Individual Parts
• Prototype

65
Designed Parts

• Inspected to determine compliance with drawings
• Critical Dimensions
• Dimensional Tolerances
• Geometric Tolerances
• Approved or Rejected

66
Assemblies

• Frame
• Suspension
• Steering
• Drive Train
• Braking
• Electrical

67
Functionality or Does it work?

68
I Dont Believe it Works

69
Prototype Testing

• Brake Test
• Top Speed
• Pulling Power
• Endurance
• Turning Radius
• Handling
• Ruggedness

70
Initial Performance Figures
71
Troubles

• Housing Bracket
• Throttle Cable
• Brakes
• Front Knuckles

72
Recommendations Conclusions
73
Frame Summary

• Turning Radius of 6 feet
• Ground Clearance of 10 inches
• Suspension Travel of 9 inches
• Frame Carries 62, 220 lb person

74
Drivetrain Summary

• Top Speed 38 mph
• Total drivetrain weight of 110 pounds
• Stops within 35 ft. from top speed
• It works!

75
Recommendations

• Machined Gearbox out-of-house
• Line-bored for bearings
• Thermoformed CVT Cover
• Shocks with Stiffer Springs
• Lower costs
• Design for manufacture and assembly principles
• Standardizing Fasteners

76
SAE Competition
Troy, Ohio June 5-8, 2003

• More Work to be Done
• Suspension increase ground clearance
• Redesign front knuckle
• Check over everything before competition
• Refine braking system
• More Testing
• Braking
• Handling and Maneuverability
• Top Speed
• Hill Climbs
• Rough Terrain
• Requirements of SAE
• Kill Switches
• Harness
• CVT Cover

77
Acknowledgments

• Teammates
• Dr. Archibald, Dr. Helfinstine
• Faculty and Administration
• Family and Friends
• Reviewers
• Geoff Gehring
• Shop Assistants
• SAE, Briggs and Stratton
• Hayes Brakes
• Hovis Auto Supply

78
Questions?