Parker Chainless Challenge - Department of Mechanical Engineering

Transcription

Parker Chainless Challenge
Hydraulic Bicycle, Volume II
ME 4054: Senior Design, Fall 2012
Sponsor: Parker-Hannifin
Advisor: Brad Bohlmann
Professor: James Van de Ven
Tan Cheng
Joe Janiszewski
Aaron Jasken
Brent Wassell
Ang Zheng
Chainless Challenge, Volume II
Table of Contents
1 – Problem Definition Supporting Documents ............................................................................................ 3
1.1
– Annotated Bibliography ............................................................................................................. 3
1.2 – Patent Search ................................................................................................................................... 4
1.3 – Additional User Needs ..................................................................................................................... 5
1.4 – Concept Alternatives and Concept Selection ................................................................................... 6
2 – Design Description Supporting Documents .......................................................................................... 13
2.1 – Manufacturing Plan ........................................................................................................................ 13
3 – Evaluation Supporting Documents........................................................................................................ 27
3.1 – Evaluation Reports ......................................................................................................................... 27
3.2 – Cost Analysis................................................................................................................................... 29
3.3 – Regulatory and Safety Considerations ........................................................................................... 29
3.4 – Environmental Impact Statement .................................................................................................. 30
2
1 – Problem Definition Supporting Documents
1.1 – Annotated Bibliography
[1] Introduction to Fluid Power: The Fluid Power Field, The Goodheart-Wilcox Co. Chapter 1.
This is an excerpt from a larger book on fluid power, and it’s applications. Chapter 1 was provided by
the publisher as a reference to the public. It was used in order to get a better understanding of the
hydraulic field in general before the design process was started.
[2] Specifications for Universities Parker 2012/2013 Chainless Challenge
This document was supplied from Parker Hannifin as a guide to the competition and its objective. The
technical requirements portion details the specific competition and race guidelines and terms.
[3] "Belt-Driven Bicycles: New Standard or Just a Fad? - Spadout.com." Belt-Driven Bicycles: New
Standard or Just a Fad? - Spadout.com. N.p., n.d. Web. 18 Oct. 2012. <http://www.spadout.com/a/beltdriven-bicycles-new-standard-or-just-a-fad/>.
This article was used to compare a standard chain design to a cog belt design
[4] "Google." Google. N.p., n.d. Web. 18 Oct. 2012. <https://www.google.com/?tbm=pts>
Site used for patent searches
[5] "Tnpsc Engineering Service." Tnpsc Engineering Service. N.p., n.d. Web. 18 Oct. 2012.
<http://tnpscengineeringservice.blogspot.com/>.
Used for images of bevel gear design
[6] Derek J, De Solla Price. "On the Origin of Clockwork, Perpetual Motion Devices, and the Compass."
N.p., 16 Nov. 2009. Web. <http://www.gutenberg.org/files/30001/30001-h/30001-h.htm>.
Used for images of planetary gear set
[7] "Speedhound Design Bureau." Speedhound Design Bureau. N.p., n.d. Web. 18 Oct. 2012.
<http://blog.speedhoundbikes.com/>.
Used for images of cog belt design
[8] Sharke, Paul. Centistokes For Different Strokes: A collegiate contest pits fluid power
against the venerable bike chain. (Design News pgs 73-77, 2/27/06).
Article on all teams in Chainless Challenge 2006
3
[9] Parker, 2007, Hydraulic Motor/Pump Series F11/F12
Motor/pump catalog Problem Definition Supporting Documents Chainless Challenge, Volume II 4
[10] 2011, "The GT1 Basic Folder," http://www.greenspeed.com
Website for the three-wheeled recumbent frame used in the design
[11] Parker, 2003, Accumulator Catalogue HY10-1630
Accumulator catalog
[12] Parker, Spool-Type, 2-Way Valve Series DS162
Solenoid valve catalog
[13] Parker, Differential Area Relief Valve Series RDH083
Relief valve catalog
[14] Parker, Check Valves Series C
Check valve catalog
[15] Parker-Hannifin. www.parker.com
Parker-Hannifin's environmental policy is available here
[16] Foley, Joseph; Huang, Qianrong; Kroll, Karl; Maxwell-Parish, Andrew; Wilcox, Jamianne;
“Parker Chainless Challenge, Hydraulic Bicycle, Volume I” ME 4054: Senior Design, Fall 2011.
Last year’s team’s report was referenced and used as a benchmark in terms of data, and used for
further analysis.
[17] Foley, Joseph; Huang, Qianrong; Kroll, Karl; Maxwell-Parish, Andrew; Wilcox, Jamianne;
“Parker Chainless Challenge, Hydraulic Bicycle, Volume II” ME 4054: Senior Design, Fall 2011.
Last year’s team’s report was referenced and used as a benchmark in terms of data, and used for
further analysis.
[18] Wooden bike. http://greenupgrader.com/4818/put-some-wood-between-your-legs-renovo/].
A wooden bicycle frame was found to claim similar structural rigidity to aluminum
1.2 – Patent Search
Patent # 3,729,213 -“Hydraulic Drive For A Bicycle.” The primary source of fluid for motor operation is
provided by a pair of hydraulic cylinders powered by the rider’s pedaling. An auxiliary flow of hydraulic
4
fluid, supplementing the fluid from the foot powered cylinders, results from the vertical motion of the
rider weighed bicycle seat during travel. Accordingly, the hydraulic flow from the foot powered cylinder
is intermittently supplemented by a fluid flow resulting from varying loads exerted on the bicycle seat
while underway.
Patent # 7,992,948 B2- “Hydraulic Regenerative Braking For A Bike.” The Bike has a regenerative braking
system assembled into a front hub of a bicycle wheel. The device allows the bicycle to capture part of
the kinetic energy that would otherwise be lost when braking and make use of that energy to assist
accelerating or hill climb maneuvers. Claim is also made that further comprising a remote actuator in
communication with the braking mechanism for selecting the mode of operation.
Patent # 4,087,105 – “Hydraulic Powered Bicycle.” This bicycle has a hydraulic motor mounted in the
rear wheel. And there are two pumps mounted on the bike. One is powered by pedaling the cranks and
the other is powered by movement of the handlebars. Power can be supplied either through cranks a
handlebars independently or at the same time. A directional control valve is used to control the flow
from pumps to motor, motor to accumulator, accumulator to motor.
Patent # 4,688,815- “Hydraulic Driven Bicycle.” This hydraulically driven bicycle consists of a hydraulic
pump mechanism and a hydraulic drive mechanism. The hydraulic pump mechanism is operated by
rotational movement of the pedal drive shaft. The hydraulic drive mechanism is driven by the fluid
pump by the pump system and is coupled to one of the wheels of the bicycle. The hydraulic pump
mechanism and the hydraulic drive mechanism are interconnected by fluid circulating tubes so that a
closed hydraulic system is constructed on the bicycle.
Patent # 5,772,225-“Hydraulic Bicycle with Conjugate Drive Motors.” This bicycle has a function of
transmitting power between mechanical movements. It includes a fluid pump and a fluid motor
attached near the rear hub, and a manifold connecting the pump and the motor. An apportionment
valve is used to control the ratio of movement between the first and second mechanical movement, and
a brake valve is used for stopping the second mechanical movement.
1.3 – Additional User Needs
In the context of the Chainless Challenge, it was determined that the main users/customers are the
competition judges themselves. Therefore, customer needs are synonymous with the competition
criterion. Table 3.1 shows a list of needs and their associated priorities.
It is important to note that the scope of the project is not to design the bike for mass production.
Although manufacturability is a factor in the competition it is not a main factor. The most important
criterion are the vehicle performs well for the 3 competitions. This is why the performance criterion is
rated higher than the manufacturability needs. The main list of needs is that the bike adheres to the
competition needs for the judges.
CATEGORY
Performance
Performance
Performance
Performance
Table 1.1 – Table of User Needs
USER NEED
Ability to pressurize in less than 10
minutes
Electronic Control System
Acceleration
Single Rider Static start
IMPORTANCE
5
4
3
4
5
Performance
Performance
Safety
Safety
Renewable Energy Design
Low Weight
Braking Distance
Stable Chassis Design
4
3
4
4
Safety
Fluid System is leak tight
5
Safety
Manufacturability
Manufacturability
Safe Accumulator Pressure
Design Complexity
Cost
5
3
3
Efficiency
Accumulator size
3
Efficiency
Accumulator Max Pressure
4
1.4 – Concept Alternatives and Concept Selection
Throughout the brainstorming process, many alternative designs were developed, and iterated upon.
The following section describes these alternatives
Transmission System
Since the project is based on the bike made by previous team and the rule has been changed, the
transmission system in front and rear has modified by the system without chain. There are several
options to complete this task.
Bevel Gear System
Bevel gears are mounted on shafts that are 90 degrees apart, which means that this mechanism can
transmit power to an output shaft that is oriented 90 degrees from the input shaft. The gear ratio is a
degree of freedom for us to optimize efficiency. Since there is limited space for mounting, the bevel gear
system solves room limitation. Although this mechanism fits the design objective, it is very heavy and
not easy to mount on the bike frame. It also requires that the shear pin has to be critically selected for
mounting it.
Figure 1.1 – Bevel gear prototype [5]
6
Planetary Gear Set
The transmission system can be replaced by gear train system directly. The efficiency can be optimized
by changing the gear ratio. However, it is also hard to mount the gear train on the bike. Based on the
experience, the gear train is not that stable since gears might be slipping due to heavy operation.
Figure 1.2 – Planetary Gear Set [6]
Cogged Belt
The cogged belt has teeth molded directly into its surface, which mesh with corresponding teeth in
pulleys. It is designed to avoid slipping and be quieter than a chain. The disadvantage is it is limited to
single speed and geared hubs
Figure 1.3 – Cogged belt application for bicycle [7]
Regeneration System
Regeneration system is used to store and re-collect energy for further using. It is designed to be used in
the efficiency race. There are several options to increase the efficiency.
7
Braking Regeneration System
There will be bonus points for adding braking regeneration system to the bike. The idea is to put one
pump on each front wheel and connect pumps back to the accumulator. It is also necessary to put some
more valves to control the braking regeneration system. After biker presses the braking button, the
pumps on front wheels will drive the hydraulic fluid to the accumulator, which saves kinetic energy in
the accumulator for future using.
Potential Different Sized Accumulators
It might be more efficient to re-size the accumulator. Since the size of the accumulator is the
determinant of how much energy can be stored, it is necessary to find an optimal accumulator for the
competition.
Pump Selection
Fixed Displacement Pumps
The fixed displacement pump causes a fluid to move by trapping a fixed amount of it and then forcing
that trapped volume into the discharge pipe. It is not necessary to use the same pump for every place.
Based on the analysis of the whole system, find the right selection of pumps for each place to optimize
the efficiency.
Variable Displacement Pump
A variable displacement pump can change the amount of fluid that is displaced per revolution of the
pump. It adds more degrees of freedom to control how much hydraulic fluid pump into accumulator per
revolution. This can be advantageous because it can allow for a lower flow rate to match high pressures,
or higher flow rate for lower pressures. The main disadvantage is that a variable displacement pump
requires more advanced controlling and is not automated.
Increase Efficiency by Reorganizing the Hydraulic Circuit
Based on the existing circuit, there are many elbow shaped hoses that would decrease the efficiency of
the whole system. It is better to replace it by the curved hoses. Moreover, simplify the existing circuit.
The shorter hoses we use in the circuit, the more efficiency it would be.
Hydraulic Circuit Selection
Several hydraulic circuits with specific characteristics are considered as options. The first circuit
developed is supposed to have energy storage function as shown in Figure 4, when valve 1 is closed and
valve 2 is open the pump will directly drive the motor. When energy needs to be stored just close the
valve 2 and open the valve 1 which will drive the fluid into the accumulator by the pump. More
completed circuits should be design based on this one.
8
Figure 1.4 – Hydraulic circuit with energy storage function
Based on the first concept, a circuit with energy regeneration and storage function is developed as
shown in Figure 5. This circuit has a path between the motor/pump to the accumulator. When the bike
begins braking, the inertia of the motor causes pressurized fluid to flow into the accumulator, and
simultaneously slows down the bike. Essentially, the bikes natural kinetic energy is transferred into
potential energy – using the resistance of the accumulator to slow the bike down.
Figure 1.5 – Hydraulic circuit with energy storage and regeneration
An improved circuit shown in Figure 6 is basically more efficient when the bike is at coast situation. It
reduces a solenoid valve compared with circuit in Figure 4, which definitely simplifies the circuit. This
circuit also contains both energy regeneration and storage function. Valve 4 is used for manually
discharge of the accumulator in case the pressure needs to be released. For safety reasons, it would
likely be a manual valve in case of an electrical or control failure.
9
Figure 1.6 – Improved circuit concept with energy regeneration and storage function
Concept Selection
Table 1.2 – Drivetrain Selection
CRITERION
CHAIN
DIRECT-GEAR
COG BELT
INLINE GEARS
PLANETARY GEARS
Cost
0
0
0
-
-
Manufacturability
0
-
0
-
-
Reliability
0
+
0
-
-
Sprint Race
0
-
0
-
-
Distance Race
0
0
0
0
0
Efficiency Race
0
0
+
0
0
Competition Points
SUMMATION
0
0
+
0
+
+2
+
-3
+
-3
By setting up a decision matrix it becomes quite apparent that there is only one logical decision. By
using a cog belt design, an effective design will be able to hit all of the major criterion for the project. If
a gear system were to be implemented, whether inline or planetary, the costs, manufacturability,
reliability and performance in the sprint race would decrease. This is because the system would have a
very low tolerance for any error and any errors that were present would not be allowed to flex as in a
cog belt design. All of the design choices would be better than using a chain for the competition
because a penalty occurs if any metal chains are used. By confirming with Parker-Hannifin that a
“nonmetal cog belt” would not be penalized, the choice becomes obvious. Not only will using a belt be
just easy costless and easy to set up as a chain, but it will also perform better [3].
10
Table 1.3 – Drive Type Selection
CRITERION
RWD (1 wheel)
FWD (2 wheels)
AWD (3 wheels)
Cost
0
-
-
Manufacturability
0
-
-
Reliability
0
-
-
Sprint Race
0
-
-
Distance Race
0
+
+
Efficiency Race
0
+
+
Competition
Points
0
0
0
SUMMATION
0
-2
-2
When selecting the drive type, how many wheels will be set up to propel the bicycle, there were three
different options. The design from last year was set up with a single RWD propulsion system. This is
also how a recumbent bicycle is designed to work (unmodified). A proper exploration of all of the
different designs was still necessary in order that an optimum result would be achieved. The main
advantages to adding motors on the front wheels are overall more power and also there would be more
energy stored in the event that a regenerative braking system is implemented. However, logistically
manufacturing an effective design that allows for motors on the front wheels introduces lots of
challenges. Mainly, due to the fact that a human has to have adequate room to pedal the bike the
motors would have to be added on the outside of the two wheels.
Figure 1.7 shows the complications of adding motors to the front of the bike. Because there is not room
on the inside, they would have to be added to the outside of the wheels. This creates a complicated
mounting scheme and also widens the base for the bike. By keeping the bike as a RWD system the
controls are simplified to only 1 motor. Additionally, since the accumulator and reservoir will likely be
mounted in the back of the bike this moves the center of mass towards the back wheel. This means that
when they bike begins to take off, frictional force will be greater because there will be more normal
force on the bike. Lastly, front motor design adds an additional complication - driving straight. If both
motors are not turning at exactly the same rate, then the bike will be “pushed” in the opposite direction.
Even if the motors are both set to the same fixed displacement, there are phantom losses throughout
the system and they will not be 100% identical. This is why a single motor RWD design is the best.
11
Figure 1.7 – Potential front motor design
12
2 – Design Description Supporting Documents
2.1 – Manufacturing Plan
The primary design of the University’s chainless bike consists of a rather limited number of outside
parts. The three wheeled recumbent bicycle frame is the primary structure which the rest of the design
is based around. An integrated fluid circuit then must be implemented onto the frame of the bike
including both a hydraulic fluid reservoir tank, along with a hydraulic fluid accumulator, in order to
transfer the energy from the users pedaling motion to the rear wheel without the use of a direct
drive. This integrated circuit also includes a control system, consisting of a series of electronically
controlled actuators to divert the flow of hydraulic fluid as desired by the user. The circuit’s electronic
components are to be powered by a solar powered 6 or 12V battery circuit. This self-sustaining
electrical circuit allows the user to ride completely independent of outside resources.
The implementation of all of those components onto the bike will allow the power generated by the
user’s pedaling motion, to be translated to the rear wheel in absence of a direct drive train. The bicycle
will also allow the user to store energy in the system’s accumulator to be made available for later access
when needed.
The University’s 2012/2013 Chainless Challenge bicycle was designed with simplicity in mind, along with
efficiency as the most crucial metric. The bicycle’s manufacturing process will consist of a rather limited
number of steps, primarily including the mounting of the system’s pumps and motors, fluid
cables/circuit, along with the energy storage/renewable apparatus.
The pump/motor mounting apparatus’ are to include a mounting plate, necessary bolts, along with a
ring mechanism for proper mounting to the bicycle. This mounting plate includes 2 holes of 0.469”
diameter, allowing it to be fastened to the side of the pump/motor. With the ring mounted around the
bike frame, one is able to bolt the motor/pump securely to the frame. The mounting plate with motor
attached, will then be fastened to the ring mechanism to be securely mounted to the bicycle frame.
These pumps and motors will also consist of a custom gear allowing the mounting of the cog belt which
is then supply the proper gear ratio from the pedals to the gear motor. This procedure is found to be
very similar for the rear motor mounting also.
Extending from the drive train, the next system component to be installed is the internal gear hub for
the rear wheel. The Shimano Alfine internal gear hub was selected for use and is to be implemented
into the rear drive system to allow for easy gear shifting. This gear shift apparatus’ is to include a gear
shift wire and will include its own installment instructions from the manufacturer. Additionally, we will
fabricate the mounts for the gear shift control mechanism. All the cables coming from the internal
geared hub should be arranged properly up to the gear shift controller, and shall have the gear shift
controller to be mounted on the handlebars of the vehicle. With the shifter oriented in this way, the
riders are able to easily control the gear shifting mechanism.
The next system component to be considered in regards to manufacturing is the mounting of the
accumulator along with the hydraulic fluid storage tank. These are both to be mounted on the rear of
the bicycle using a heavy duty clamp-bolt system, with most of the weight being rested on the mounted
rack. Considering the weight of the accumulator (~50lbs), one is to make certain the mounting rack is
stable and void of any deflection.
13
Parts Drawings
Figure 2.1 – Parker Hannifin 3000PSI, 1 Gallon Accumulator
14
Figure 2.2 – Pump and Motor
15
Figure 2.3 – Motor Mounting Platform
16
Figure 2.4 – Pump Cage Mount
17
Figure 2.5 – Pump Mounting Platform
18
Figure 2.6 – Series DS162 Spool - Type, 2 - Way Solenoid Valve
Figure 2.7 – Series RDH083 Differential Area Relief Valve
19
Figure 2.8 – Series C Check Valve from Parker - Hannifin
Bill of Materials
Description
F11
pump/motor
Greenspeed
GT1
Recumbent
Bicycle
1 gallon
bladder
accumulator
3000 psi
Alfine Disc
or Rim Brake
8-spd
Internal Hub
(32-Hole,
Black)
60 tooth
CDX –
Center-Track
Sprocket
20 tooth
CDX –
Center-Track
Sprocket
24 tooth
CDX –
Center-Track
Alfine
Sprocket
113 tooth
Qty
Total
Team
Cost
Production
Cost
0
2
0
2197.6
0
1
0
1889.97
Retail
Cost
Team's
Cost
1098.8
1889.97
Source
Parker
Hannifin
Part Number
F11-005
3707308
Calhoun
Cyclic
GRS-4011
Parker
Hannifin
BA01B3T01A1 851.55
0
1
0
851.55
Amazon
SG-S501
253.44
253.44
1
253.44
253.44
Erik’s Bike
Shop
SO104999
104.99
104.99
1
104.99
104.99
Erik’s Bike
Shop
SO8999
89.99
89.99
1
89.99
89.99
Erik’s Bike
Shop
Erik’s Bike
SO104999
SO10999
104.99
109.99
104.99
109.99
2
1
209.98
109.99
209.98
109.99
20
CenterTrack
belt
125 tooth
CenterTrack
Belt
Surly Nice
Bike Rack
Metric
Keyway
Broach
Shimano
Alfine Rapid
Fire Shifter
6-Volt Solar
Panel
Arduino Kit
6" D PVC cap
Gallon of
hydraulic
Fluid
6v Battery
Alfine/Nexus
small parts
kit
3/8" Thick
6061
Aluminum
Sheet, 4"X3'
Bushing for
Metric
Keyway
Broach
Jumper
Wires
Battery
Charger
22 Gauge
Wire
Nexus
Sprocket
(18T)
LED Pack
Clamping UBolts
Breadboard
Shim for
Keyway
Shop
Erik’s Bike
Shop
Calhoun
Cycle
SO10999
319.99
319.99
1
319.99
319.99
SUR-0102
135.97
135.97
1
135.97
135.97
McMaster
Carr
8805A16
61.65
61.65
1
61.65
61.65
Amazon
SL-S500
49.99
49.99
1
49.99
49.99
Amazon
Amazon
Menards
-
24.1
36
11
24.1
36
11
2
1
2
48.2
36
22
48.2
36
22
Amazon
-
20
9.52
0
9.52
1
2
0
19.04
20
19.04
Amazon
SG-S501
18.58
18.58
1
18.58
18.58
13.5
0
1
0
13.5
ME Tool Crib
McMaster
Carr
8804A24
12.21
12.21
1
12.21
12.21
Amazon
-
9.93
9.93
1
9.93
9.93
Amazon
D1724
7.81
7.81
1
7.81
7.81
Amazon
-
3.39
9.01
2
18.02
6.78
Amazon
Amazon
McMaster
Carr
Amazon
McMaster
Carr
SG-3C40
-
6.47
6.44
6.47
6.44
1
1
6.47
6.44
6.47
6.44
3042T74
-
1.59
5.5
1.59
5.5
4
1
6.36
5.5
6.36
5.5
8836A35
2.74
2.74
2
5.48
5.48
21
Broaches
8" length of
6" diameter
PVC pipe
Clamping UBolts
Speaker
Hub Shift
Cable Fixing
Bolt Unit
Jumper Wire
2.2K Ohm
1/2W
Resistor
10K Ohm
1/2W
Resistor
1K Ohm
1/2W
Resistor
100K Ohm
1W Resistor
8-32 Set
Screws 1/4" Length
Cog Belt
(Front)
Cog Belt
(Rear)
Industrial
Fitting Tube
To Straight
Thread
(IFTTST)
Industrial
Fitting
Component
(IFC)
(IFC)
(IFTTST)
(IFC)
(IFC)
Industrial
University of
Minnesota
McMaster
Carr
Amazon
5
0
1
0
5
3042T77
-
1.72
0.95
1.72
0.95
2
3
3.44
2.85
3.44
2.85
Amazon
Amazon
-
2.45
1.98
2.45
4.61
1
1
2.45
4.61
2.45
1.98
Amazon
-
0.98
5.54
1
5.54
0.98
Amazon
-
0.98
5.54
1
5.54
0.98
Amazon
-
0.98
5.54
1
5.54
0.98
Amazon
-
0.98
5.54
1
5.54
0.98
0.43
0.43
2
0.86
0.86
0
0
0
0
Parker
Hannifin
Parker
Hannifin
Parker
Hannifin
Parker
Hannifin
Parker
Hannifin
Parker
Hannifin
Parker
8 F5OX
6
0
0
8 TX
6
0
0
8 BTX
6
0
0
4-6 F5OX
4
0
0
6 TX
4
0
0
6 BTX
8JTX
4
2
0
0
0
0
22
Fitting Tee,
Tube
Industrial
Fitting Tee,
Tube
Hydraulic
Hose
TOTAL
Hannifin
Parker
Hannifin
Parker
Hannifin
4JTX
1
0
0
451TC-8
1
0
1679.39
0
6624.90
Manufacturing Procedure
The following manufacturing procedure has been broken down into eight steps. They are each
described below in sufficient detail to allow anyone to be able to manufacture the bicycle that has been
described throughout this report.
Figure 2.9 – Factory Stock Recumbent Bike
The first manufacturing objective present in regards to the assembly of hydraulic bike design is to install
and implement both the motor and pump assemblies.
1) The mounting plates along with the motors are shown as follows with step denotations. 1- Begin by
inserting the 10-32 X ⅝” round head machine screw through the hole of the pump’s mountain platform.
Make sure to fasten screws tightly. 2- Once having assembled the plate to the mounting rings, attach
the U-Channel plate to the side of the pump as seen below and fasten with the given 1.75” U-Bolts.
23
Figure 2.10 – Motor/Pump Mounting Assembly
Figure 2.11 – Front Pump Assembly
2) The mounting procedure for both the front and rear motor is very similar. The rear motor’s U-Bolt for
mounting is slightly larger at 2.125” and attaches to the bicycle as seen below in Figure ().
Figure 2.12 – Rear Motor Assembly
24
3) The motor and pump sprockets also needs to be connected with the belt sprockets with 1/4” bolts
together. The belt sprocket will be further fabricated by drilling 5 holes that are evenly distributed
around a circle concentric with the sprocket. And the pump/motor sprockets will have 5 corresponding
holes to be drilled for the use of bolts connection. Inside the pump/motor sprockets a rectangular slot
will be milled from the material. And one 6mm key is cut into the bored hole using a broach and arbor
press so that the pump/motor sprocket can have a fitting contact with the spindle of motor and pump.
4) The pump sprockets also need to be connected with the belt sprockets with 0.6 cm bolts together.
The belt sprocket will be further fabricated by drilling 6 holes that are evenly distributed around a circle
concentric with the sprocket. And the pump/motor sprockets will have 6 corresponding holes to be
drilled for the use of bolts connection. Inside the pump/motor sprockets a rectangular slot will be milled
from the material. And one 6mm key is cut into the bored hole using a broach and arbor press so that
the pump/motor sprocket can have a fitting contact with the spindle of motor and pump.
Figure 2.13 – Custom Sprocket for Pump/Motor
5) Attach the cog belt along with its pulley assembly. To do this, one must first have the sprocket
machined onto the motor/pump using an outside professional source to do so. Once having this
sprocket, follow Carbon Drive System’s Technical Installation Guide provided for mounting the carbon
drive and actual belt.
Figure 2.14 – Cogged Belt [xxx]
6) Attach the accumulator and reservoir to the sides of the real rack as shown below in Figure (2.x) .
The system will include a mounting clamp apparatus which is to be fastened to the side of this rack.
25
Figure 2.15 – Bike with Pump and Accumulator Connected
7) Once having the tanks mounted, attach the solenoid valves to the hydraulic circuit, along with the
tanks. Fill the tanks with designated hydraulic fluid and cycle the pump to fill the lines with fluid.
Figure 2.16 – Close up of reservoir
8) Next, attach the solenoid valves to the platform underneath the bicycle seat. Follow the hydraulic
circuit diagram to assure the system is assembled properly. Fill the storage tank with appropriate
hydraulic fluid and allow the system to properly circulate all fluid.
26
3 – Evaluation Supporting Documents
Although the binary evaluations have been performed, and the results discussed in Volume I of this
report, the remaining quantitative analysis cannot be performed until the spring semester of 2013 as
the team optimizes the design, and prepares for competition occurring in April 2013. However, the
evaluation that last year’s team performed has been referenced, and is also summarized below. The
results of these tests have given this year’s team a very good understanding of the bicycles
performance, and provided solid benchmark numbers for comparison purposes. Refer to the design
report below for one example of last year’s team’s analysis that was referenced in order to establish
benchmark numbers.
3.1 – Evaluation Reports
Human Pedaling Capabilities [16],[17]
INTRODUCTION
One of the design requirements of the hydraulic bicycle is that it must be powered by a single human. In
order to ensure that a single person will be capable of powering the design, an experiment was
performed to determine human pedaling capabilities. Using theoretical equations, the hydraulic pump
and motor were sized based on human pedaling capabilities and the torque requirements for moving a
bicycle.
The three pumps/motors that Parker Hannifin are providing free of charge are the F11-005, F11-010,
and H310. The F11-005 is a bent axis pump with a displacement of 5cc/rev. The F11-010 is a bent axis
pump with a displacement of 10 cc/rev. The H310 is a gear pump with a displacement of 10 cc/rev.
Although a pump from a different company could have been purchased, only the three pumps from
Parker Hannifin were evaluated because they were free and were recommended by Parker Hannifin.
Important Governing Equations
Equation 3.1)
q = Flow rate [L/min]
D = Displacement [cc/rev]
N = Shaft speed [rpm]
nv = Volumetric efficiency
Equation 3.2)
T = Torque [N*m]
Δp = Differential pressure across pump [bar]
nm = Mechanical efficiency
Equation 3.3)
P = Power [kW]
nt = nm* nv = overall efficiency
27
Equation 3.4)
P = Power [W]
T = Torque [N*m]
w = Pedaling speed [rpm]
METHODS
The Precor UBK 835 upright stationary bike is shown in Figure 3.1. The power and pedaling speed were
displayed on the digital screen of the machine.
Figure 3.1 – Precor UBK 835 Exercise Bike
Data Acquisition Procedure
 The bicycle was pedaled to a point that felt like a sustainable speed and maintained at this
speed.
 The power and pedaling speed were recorded from the digital output of the bicycle.
 This was repeated 3 times to ensure accuracy.
 The above was repeated for a maximum pedaling speed by pedaling as hard as possible.
Data Analysis Procedure
 The human torque capabilities were calculated using Equation 3.4.
 The pressure increase was calculated for each pump size using Equation 2.2.
 A spreadsheet was used to calculate torque requirements for a bicycle.
RESULTS
Using the Precor Stationary Bike in the University of Minnesota Rec Center, the human pedaling
capabilities were determined. Using the power and rpm measurements, the torque capabilities were
calculated. It will be assumed that the torque capabilities for a recumbent bicycle are the same as that
for the Precor upright stationary bicycle. In reality, a human can produce slightly higher torque on a
recumbent bicycle because the back muscles can be better utilized in a recumbent position. The results
are summarized in Table 3.1.
28
Sustainable
Maximum
Table 3.1 – Human pedaling capabilities
Power [W]
RPM
150
80
425
125
Torque [N*m]
18
32
3.2 – Cost Analysis
In order to adequately determine the overall cost to manufacture the bicycle, previous costs assumed by
last year’s team have to be incorporated, i.e. the cost of the frame, hoses, fittings, etc. These costs were
not expensed by this year’s team; however they still need to be accounted for. Therefore, the overall
cost of bicycle that has been designed this year, referencing the bill of materials from both this year and
the previous year, amounts to $6624.90.
This is a fairly high cost at first glance; however, the hydraulic pump and motor, the accumulator, and
the frame make up more than 50% of these costs. It is likely that a large manufacturer would be able to
achieve some sort of economies of scale in order to reduce this overall price. It is estimated that this
bicycle could be produced for under $4000 dollars by a manufacturer. This price includes a 40%
reduction in the most expensive components of the design due to economies of scale, as well as the
labor of 3 full time manufacturing personnel assembling the bicycles at $12 per hour at a rate of 6
bicycles per hour.
The market these bicycles would be selling in is the high-end bicycle-enthusiast market. Other bicycles
in this market retail for around $4000. This places the team’s design in direct competition with these
other high-end models. One differentiating factor that this bicycle has is the fact that it is hydraulically
powered, and has both an energy storage (accumulator) and energy recovery (solar) system built into.
The team believes that these factors would
3.3 – Environmental Impact Statement
The impact that any given design has on the environment is very important. Virtually every design
impacts the environment in some way. In the case of this bicycle, the environment was considered in
numerous areas. For instance, the use of bio-degradable hydraulic fluid, i.e. a fluid that is not mineral
based, is less harmful to the environment. This type of fluid was incorporated into the final design.
Additionally, solar recovery reduces the wear on the batteries, which means that they will have to be
replaced less often. This component could be taken one step further and a completely solar powered
control system could be implemented in the future. Refer to the remaining section below for more
information on the environmental impact of the final design.
Purpose and Need
With the World’s natural minerals rapidly depleting, and the World-wide effort to reduce harmful
emissions and green-house gasses, there is definitely a need for alternative modes of transportation.
This hydraulic-powered bicycle is a perfect example of such an alternative. This design has a positive
impact on society by utilization solar energy, and energy storage.
Impact to Environment
This design is going to change the environment in a positive way by raising awareness of alternative
modes of transportation. This bicycle being so unique will likely catch the eye of progressive consumers,
which will aid in the conversion of society to change their old energy habits. A bicycle like this does not
pollute as a car or other small motorized vehicle does. The hydraulic fluid used is bio-degradable, and
29
disposable, and the frame and all of the mounting components are made out of aluminum which is also
easily recyclable.
Alternatives to Design
One way to increase the friendliness of this design in regards to the environment is if the hydraulic
pump and motor could be manufactured to be more easily recyclable. Additionally, if the rubber hoses
could be manufactured without the use of steel braiding, this would make them easier to recycle as
well.
Discussion
Throughout the entire design process, the environment was considered. In society today, it is virtually
impossible to design anything without first analyzing its impact on the environment. If it would have
been possible to partner with Parker-Hannifin in the development of more environmentally friendly
hydraulic component hardware, it would have been interesting to see what would have resulted. Future
work might include incorporating more aluminum rather than steel into hydraulic fittings, removing
steel braiding from hydraulic hoses, and designing more accumulators that are made out of more easily
recyclable materials. Additionally, the frame could be reconsidered to be made out of wood instead of
aluminum. There are, in fact, frames made out of certain types of wood that are said to be as
structurally sound as aluminum and other metals [18].
3.4 – Regulatory and Safety Considerations
As with mostly all hydraulic systems, pressure is the most dangerous component. With operating
pressures near 3000 psi, it is crucial that necessary design considerations be made. It is important to
ensure that all hoses, fittings, motors, etc. are rated to withstand the given operation pressures with
sufficient safety factors. If the pressure were to become too large, significant injuries could occur.
Aside from pressure considerations, since the bicycle is technically a moving vehicle that can reach
speeds of upwards of 30 mph, it is important to also consider a method of braking. If these types of
speeds are achieved, the user must be able to come to a stop promptly and safely. This year’s team’s
bike has two front wheel bicycle disk brakes that allow this safe deceleration to occur.
30

Parker Chainless Challenge - Department of Mechanical Engineering

Transcription

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