The TEAMMATE

The TEAMMATEA Mechanical Regenerative Braking Design Project

Winter 2013Team Eight

1

The Team• John El-Tawil• Colin MacKenzie• Michael Matthews• Alan Robinson

• Dr. Marek Kujath

Supervisor

2

Outline

• Introduction

• Design

• Testing

• Design Requirements

• Budget

• Summary & Recommendations3

Scope

• Design/build a mechanical regenerative braking system

• Capture energy dissipated during braking of a bicycle

• Lower input energy to accelerate from stop

• Improve rider efficiency

Intro Design Testing Design Requirements Budget Summary

4

The Design

5


The Spring• System uses a spiral

torsional spring

• Issue: Input is CW Output is

CCW

• Solution: Charge outside Release

inside

6

Figure 1 – Spiral Torsional Spring


How the Spring will Work

1.

3.

2.

4.

7

Figure 2 – Spring Dynamics


Custom Axle

8

Figure 4 - Custom Hub

(Shimano, 2013)


Figure 3 – Standard Hub

Custom Axle

9


Figure 5 – Custom Axle

10

The System


Figure 6 – The System

Input Shaft

11


Figure 7 – The Input Shaft

12

The System


Figure 8 – The System

Output Shaft

13


Figure 9 – The Output Shaft

Manual Control / Operation

14


Figure 10 – The Manual Control Triggers

Testing

• Friction losses from system

• Weight losses from the system

• Energy gained from the spring

15


Figure 11 – Testing

Test # 1: Friction Losses• Energy could be lost in the system from bearing

friction

• A speed test was run 5 times with chains attached

and detached

• Final speeds were averaged and compared to determine if there were losses in energy

16


Friction Losses

ChainedRuns Final Speed Elapsed Time (s)

1 17.8 5.3

2 20.2 4.8

3 17.8 5.3

4 15.4 5.5

5 17.7 5.2

Mean 17.78 5.22 17

Not ChainedRuns Final Speed (km/h) Elapsed Time (s)

1 17.7 5.3

2 16.7 5.4

3 19.9 5.1

4 17.6 5.2

5 19.6 5.0

Mean 18.3 5.2

Table 1 – Average speed with system not chained

Table 2 – Average speed with system chained

Friction Losses

18

• Assuming no losses from friction, the final velocities should be the same

= 97.2%

• Losses were minimal with system engaged

• Therefore friction losses neglected in energy balance


Test # 2: Weight Losses• Energy lost due to added weight of the system (8.98 kg)

• Accelerating a mass requires energy

• The difference in accelerating the bicycle with and without the system will show the energy taken to accelerate just the system from rest.

19


Weight LossesWith System

Run Distance Travelled (m) Time (s)1 24.31 9.58

2 19.88 7.46

3 23.38 8.65

4 23.38 8.84

5 24.16 9.39

Mean 23.02 8.78

20

Without SystemRun Distance Travelled (m) Time (s)

1 21.93 7.84

2 20.66 7.33

3 20.66 7.45

4 18.81 6.54

5 23.38 8.01

Mean 21.09 7.43

Table 3 – Distance and time for acceleration with system

Table 4 – Distance and time for acceleration without system

Weight Losses

• extra needed to accelerate the system mass after each stop

21

Test # 3: Energy Gained • Spring ‘’ obtained through testing using torque sensor ratchet

()

• Rotational angle for a max charge, 270 degrees

• Spring’s K and max lower than ideal

• Limits system benefits

22


Testing Results

• Rider uses 16.1 J less than they would without the system per acceleration

• The total savings will increase based frequency of use

• 34 KJ saved per semester for one team member.23


Testing Summary• Showed overall net gain in energy while using the

“TeamMate”

• Energy gain is very low, but can be improved with two simple design improvements:• Reduce system weight (cast iron and steel not required)• Custom torsional spring (higher K and greater

• The output chain can slip in high torque situations24


Key Design Requirements

25


Requirement Status Details

Must not reduce functionality

Cannot reverse

Improved Rider Efficiency +16.1 J per charge

Propel rider and bike mass of 100 kg

88.8 kg

Assist in acceleration Balance Manually controlled engage and disengage Fatigue 100 charge cycles

Budget

26

Supplies Supplier Acquired Projected Cost Actual Cost Differential

Mounting System Bicycle Canadian Tire Y $ 345.00 $ 344.92 $ 0.08

Back Rack Cyclesmith Y $ 70.00 $ 46.00 $ 24.00

Containment Box Home Depot Y $ 110.00 $ 160.80 -$ 50.80

Hinges Home Depot Y $ 20.00 $ 3.59 $ 16.41

Bolts Fastenal/Home Depot Y $ 20.00 $ 68.99 -$ 48.99

Aluminum Metals 'r' Us Y $ 200.00 $ 48.88 $ 151.12 Mechanical Transmission System

Sprockets Cyclesmith Y $ 215.00 $ 58.98 $ 156.02

Bicycle Chains Canadian Tire Y $ 80.00 $ 87.39 -$ 7.39

Mounting Shafts/Steel Metals 'r' Us Y $ 40.00 $ 66.76 -$ 26.76

Derailleur Cyclesmith Y $ 50.00 $ 156.57 -$ 106.57

Bearings Princess Auto Y $ 100.00 $ 166.68 -$ 66.68

Disc Brake Axle Ideal Bikes Y $ 70.00 $ - $ 70.00

Energy Storage System

Spiral Torsional Spring John Evans and Sons INC. Y $ 100.00 $ - $ 100.00

Pins Dalhousie Machine Shop Y $ 40.00 $ 5.61 $ 34.39

Disc Brake Assembly Cyclesmith Y $ 150.00 $ 68.99 $ 81.01

Manual Control System

Gear Shifters Ideal Bikes Y $ 60.00 $ 28.75 $ 31.25

Dual Pulling Brake Lever Ideal Bikes Y $ 70.00 $ 46.99 $ 23.01

Locking Brake Lever Ideal Bikes Y $ 70.00 $ - $ 70.00

Shifter Cables Canadian Tire Y $ 10.00 $ 9.18 $ 0.82

Miscellaneous

Wheel Building Ideal Bikes Y $ - $ 113.84 -$ 113.84

Handle Home Depot Y $ - $ 1.15 -$ 1.15

Tools Cyclesmith Y $ - $ 19.17 -$ 19.17

Wheel Stand Ideal Bikes Y $ - $ 287.49 -$ 287.49

TOTAL $ 1,820.00 $ 1,790.73 $ 29.27

REMAINING $ 29.27


Mounting

Mech System

Storage System

Manual Control

Misc.

Future Recommendations

1. Custom torsional spring

2. Reduce weight

3. Add output tensioner

27

4. Different bicycle

5. Custom back rack

6. Better bearings


Acknowledgements• Angus• Albert, Mark• Dr. Marek Kujath • Dr. Ted Hubbard, Dr. Clifton Johnston• Ideal Bikes• Cyclesmith• Master Auto• Supermileage Team • Dr. Robert Bauer 28


Questions?29

Website: http://poisson.me.dal.ca/~dp_12_08/Twitter: @MechTeamEight

http://poisson.me.dal.ca/~dp_12_08/



Key Ring

IntroDesign

Requirements

Design Testing Budget Summary

30

Key Ring

Maximum Torque Required to Accelerate a Bicycle

Basic Parameter Value ChosenProvided by

Manufacturer Total Mass of

Bicycle and Rider100 kg

Initial Velocity 0.0 m/s Final Velocity 15 km/hr (= 4.2

m/s)

Distance 10 metres Frontal Area of Average Rider

5.5 ft x 2 ft

= 11

(=1.022 )

Diameter of Bicycle Wheel

.800 m

31

Assume is based on air resistance at and

(1.022 )

NOTE: 5.63 N was increased to 10 N to compensate for relative wind velocity and neglected mechanical losses in bicycle.

(9)(10)

= 44.0 Nm (11)

NOTE: It was later determined through testing that the maximum torque required was approximately 35.0 Nm but to maintain a conservative approach, all following calculations are based on 44.0 Nm. 32

Safety Factor of Bicycle ChainBasic Parameter Value Chosen

Provided by Manufacturer

Maximum System Torque

44.0 Nm (= 33 ft-lb)

Maximum Allowable Force in Low Quality

ANSI 40 Chain (Standard Bicycle

Chain)

940 lb

Minimum Sprocket Diameter (12 Teeth)

1.5 in

S.F. = = 1.78

33

Safety Factor of Bicycle SprocketsBasic Parameter Value Chosen

Provided by Manufacturer **

Minimum # of Sprocket Teeth

12

Sprocket Material Steel 1045 Shear Area of Sprocket

Tooth 2.0 x

Force in Chain

Minimum Chain Wrap Angle

120

S.F = 34

Safety Factor of Disc BrakeBasic Parameter Value Chosen

Provided by Manufacturer

Maximum System Torque

44.0 Nm (= 33 ft-lb)

Maximum Pinching Force of Disc Brake

1200 lbf

Radius of Disc Brake 80 mm of Steel Rotor on Brake

Pad.67

Safety Factor

35

Safety Factor of Spiral Torsional Spring

Basic Parameter Value ChosenProvided by

Manufacturer **Maximum System Torque 44.0 Nm (= 33 ft-lb) Maximum Spring Angle of

Deflection240

Spring Rate ‘K’ 4.2312

Safety Factor

36

Safety Factor of Shafts Subjected To Torsion

Basic Parameter Value ChosenProvided by Manufacturer

**Maximum System Torque 44.0 Nm (= 33 ft-lb)

Shaft Diameter 1.5 in= 38.1 mm

Shaft Material Steel 316 (Stainless)

Safety Factor

37

Safety Factor of Shafts Subjected to Shear

Basic Parameter Value Chosen Provided by Manufacturer Maximum System Torque 44.0 Nm (= 33 ft-lb)

Shaft Diameter .75 in= 19.05 mm

Shaft Material Steel 316 (Stainless)

Safety Factor

38

Test # 4: Energy Storage System Efficiency

• Compare input and output speeds on the stand

• With and without torque resistance

39

Intro Design

Testing

Design Requirem

ents

Budget

Summary

The TEAMMATE

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