Express-O Commuter Trike DESIGN PROJECT PRESENTATION Department of Mechanical Engineering Dalhousie University Halifax, Nova Scotia

Team 4 – Express-O Clients Supervisor Dr. A. Warkentin Dept. of Mechanical Eng. Dalhousie University Matthew Rockwell Matthias Eisengruber Jayme Whalen Patricia Gillis Ahad Ahmed

Problem Definition PROBLEM SOLUTION Congested Highways Increase in Commuter traffic in HRM Congested Highways Environmental Pollution Parking space shortages SOLUTION Environmentally Friendly Reduce traffic congestion Average business person

Express-O Design Drive Train Frame Braking Banking Steering

Rear Triangle from Bicycle Frame and Seat Re-use rear triangle Adjustable seat 60o from Horizontal 1 3/8” Chromoly Steel Tubing Rear Triangle from Bicycle

Drivetrain 80 rpm [ Comfortable, Efficient pedal cadence Gearing 3 X 7 Rear drive train Fixed ratio Front drive train

Drivetrain High Gear 1 : 3.5 Gear Ratio Max Speed @ 80rpm input: 35 km/h Low Gear 1 : 0.69 Gear Ratio Max Speed @ 80rpm input = 6.8 km/h Front Middle Rear

Chain Routing

Braking Dual Front Disc Brakes Radical© Brand Mechanical Disc Brakes

Tilting: Theory Shifts Center of Gravity Normal Force on inside wheel is increased Tipping occurs when Normal force = 0 D F mg FF A y x a b FN y y H H

Tilting: Theory Turning Velocity h Stability in Turns h

Tilting: Links Thickness of Link – 1” thick x 1.5” high Holes for bushing and spring housing Bushing Horizontal Tilt Link Diamond Plate

Steering: Theory Ackerman Steering Centre Point Steering Caster Effect Wheel Camber

Steering: Rider Input Vertical Steering Arms Located at both sides of the rider Can move forward and backward Connected to L-bracket on bottom of the stub axle

Manufacturing Parts needed for Assembly : Qty 88 Parts Tasks: Acquisition of Material Off the Shelf – 44 parts Student built – 32 parts Technician Built – 12 parts Dimensioning Machining Welding Assembly

Major Design Changes Tilting System Materials Brakes Drive train

Changes to Tilting System Replaced bearings with bushings Closer fit More contact surface Added springs Static stability Return from banking position

Changes to Materials Most parts originally designed to be fabricated from steel To reduce weight, cost some parts were fabricated from aluminum These include: Horizontal tilt links Steering L-brackets Steering arms

Changes to Brakes Omitted rear V-brake Vehicle now has dual front disc brakes only Disc brakes provide sufficient braking power Simplified the braking system

Changes to Drive Train Originally designed to have three derailleurs Now has two derailleurs Lower gear ratio

Analysis Finite Element Analysis Design Requirements: Horizontal Tilt Links Stub Axles Design Requirements: Survive: 5Km/H impact with curb 0.16 m drop off curb Safety Factor: 3

FEM RESULTS Max Force: Max Stress: Al 6061 T6 Yield Strength: 1800 N 90 MPa Al 6061 T6 Yield Strength: 276 MPa

Stub Axles Max Force: 1020 Steel Yield Strength: 1800 N Max Stress: 200 MPA 1020 Steel Yield Strength: 346 MPa

Future Improvements Horizontal Tilt Link Mounts Chain Pulley Brackets Spherical Ball Ends Spring and Damper Set Up Seat

Horizontal Tilt Link Mounts Problem: Cantilevered Bolt acts a Pivot Bolt bends when forces act on Links Fix: Second Diamond Plate

Chain Pulley Brackets Problem: Fix: Cantilevered Bolt Bolt bends when Chain is under tension Regular Idler Gear not designed to run on an angle Fix: Second Adjustable Plate

Spherical Ball Ends Problem: Fix: Inexpensive Rod Ends with unknown load rating Not quite enough freedom to move Premature Failure Fix: Higher Budget to buy specked out Rod Ends

Spring and Damper Set Up Problem: Springs need to be adjusted according to rider weight for smooth banking Banking motion is not continuous Fix: Adjustable Spring Mounts Light Damper to “smooth out” banking motion

Seat Problem: Fix: Not enough side support Makes leaning into corners harder Fix: Deeper Sling Seat Design

Accessories Lexan/Plexiglas Enclosure Lights Flag More Storage Compartments Toolkit Cup holder

Original Scope Ergonomics Safety Durability Materials Costs Complexity Physical Specs Ergonomics Materials Costs

Safety Safe to operate Visible in traffic Stable Durable Protection of rider from moving parts

Durability Withstand environmental conditions This has not been fully tested Withstand road conditions (i.e. potholes) Seems to ride well on road surfaces Survived speed bumps!

Complexity Simple & Functional Easy to Manufacture & Repair Standard “off-the-shelf” Parts Brakes Wheels Chaining Rear Triangle

Physical Specs Original Dimensions Actual Dimensions Width: 1.5m Length: 3m Height: 2m Weight: 50kg Actual Dimensions Width: 1.12m Length: 2.15m Height: 0.82m Weight: 29kg

Ergonomics Sized comfortably for one adult Adjustable seat to pedal distance Seat at a comfortable height Simple to operate Intuitive steering Learning curve to mastering tilting Easy to Mount/Dismount Relatively easy – except position of tilt links

Ergonomics (continued) Reduced physical power input Relatively easy to pedal Protection from weather Not included due to time and money Options for future adaptations Cargo Space to fit backpack/briefcase Rack over rear wheel Extra space behind seat

Materials Minimize costs and meet design requirements Recycled Parts Donated Material Light, durable, easily machined Changed some parts to aluminum Durability issues with the chaining Stub axles were the most complicated part

Cost Ceiling price of $2000 Total estimated cost $1221.96 ($785.95 with donations) Actual cost $825.15 Keep cost to a minimum Donated Material Recycled Parts Money Donations Necessary but expensive parts Additional costs for bolts, springs, etc.

Criteria Table Criteria Satisfied Room for Improvements Safety  Durability Complexity Physical Specs Ergonomics Materials Costs

Testing Performance Goals Turning Radius Cruising Speed Maximum Speed Stability Stopping Distance Reliability

Cornering / Turning Radius Goal Capable of maneuvering on city streets Test Result Acceptable turning radius of 6m @ 15km/h

Cruising / Max Speed Goal Test Result Comfortable cruising speed of 15km/h Maximum speed of approximately 50km/h Test Result 15km/h is easily attainable Maximum Speed obtained of 45km/h

Stability Goal Test Result Stable when stationary (i.e. Stoplight) Stable at high speed Stable while cornering Test Result Stable with the aid of front brakes and practice Low speed stability is slightly less than desired High speed stability is as expected Performs very well at high speeds “Hugs” tight corners at high speeds

Stopping Distance Goal Test Result Maximum stopping distance of 6m At cruising speeds (~15km/h) : <2m At max speed (45km/h): 7m

Reliability Goal Test Result 1350km/year with minimal maintenance Chain tension system on the prototype is not very reliable Tilting linkage would require frequent adjustment

Conclusion Performance  Size and Weight  Cost  Safe  FUN 

Thank You Angus & Albert Paddy Wong & Zack Gus Reed Sportwheels & Bike Doctor Dr. Warkentin

QUESTIONS?