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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
Intro Design Testing Design Requirements Budget Summary
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
Intro Design Testing Design Requirements Budget Summary
How the Spring will Work
1.
3.
2.
4.
7
Figure 2 – Spring Dynamics
Intro Design Testing Design Requirements Budget Summary
Custom Axle
8
Figure 4 - Custom Hub
(Shimano, 2013)
Intro Design Testing Design Requirements Budget Summary
Figure 3 – Standard Hub
Custom Axle
9
Intro Design Testing Design Requirements Budget Summary
Figure 5 – Custom Axle
10
The System
Intro Design Testing Design Requirements Budget Summary
Figure 6 – The System
Input Shaft
11
Intro Design Testing Design Requirements Budget Summary
Figure 7 – The Input Shaft
12
The System
Intro Design Testing Design Requirements Budget Summary
Figure 8 – The System
Output Shaft
13
Intro Design Testing Design Requirements Budget Summary
Figure 9 – The Output Shaft
Manual Control / Operation
14
Intro Design Testing Design Requirements Budget Summary
Figure 10 – The Manual Control Triggers
Testing
• Friction losses from system
• Weight losses from the system
• Energy gained from the spring
15
Intro Design Testing Design Requirements Budget Summary
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
Intro Design Testing Design Requirements Budget Summary
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
Intro Design Testing Design Requirements Budget Summary
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
Intro Design Testing Design Requirements Budget Summary
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
Intro Design Testing Design Requirements Budget Summary
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
Intro Design Testing Design Requirements Budget Summary
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
Intro Design Testing Design Requirements Budget Summary
Key Design Requirements
25
Intro Design Testing Design Requirements Budget Summary
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
Intro Design Testing Design Requirements Budget Summary
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
Intro Design Testing Design Requirements Budget Summary
Acknowledgements• Angus• Albert, Mark• Dr. Marek Kujath • Dr. Ted Hubbard, Dr. Clifton Johnston• Ideal Bikes• Cyclesmith• Master Auto• Supermileage Team • Dr. Robert Bauer 28
Intro Design Testing Design Requirements Budget Summary
Questions?29
Website: http://poisson.me.dal.ca/~dp_12_08/Twitter: @MechTeamEight
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 Requirements
Budget
Summar
y