Multi-Disciplinary Engineering Design Conference
Kate Gleason College of Engineering
Rochester Institute of Technology
Rochester, New York 14623
Project Number: P11511
BEARING LIFE TEST FIXTURE
Team Members:
Kevin Argabright / Project Leader
Fitch Dean / Lead Engineer
Justin Eichenberger / Project Engineer
Michael Buonaccorso / Project Engineer
William Nowak / Project Guide
Dr. Stephen Boedo / Faculty Advisor
Xerox Corporation / Corporate Sponsor
ABSTRACT
INTRODUCTION
The bearing life test fixture is designed to collect data
while a ball bearing is running through its theoretical
life cycle. Data will be collected through the use of an
accelerometer, which will continuously collect
information while the bearing is under load. Loading
conditions include heating the bearing to 230°F,
applying an axial load of 360 lbs, and rotating the
bearing at 79.8RPM. The outer race of the bearing is
fixed, while the inner race spins. The fixture is
currently not operational. The fixture is currently not
operational. Future work can be performed to correlate
data taken from the fixture with the actual life cycle of
the bearing.
Printers are complex pieces of machinery that include
many parts that all move together to get the most
precise image quality possible. The Xerox Corporation
has been a leader in the printer and copier industry,
paralleled by none in terms of quality and durability.
The fuser roll in the iGen unit sees many different
forces and loads as the printer runs its cycle. The heat
rolls apply heat to the fuser, while the pressure roll
applies the force needed to cure the image to the
paper. All these loads are seen by the bearings that
support the fuser roll, one on each side of the roll.
NOMENCLATURE
CAD (Computer Aided Design) - the use of
computer technology for the process of design and
design documentation
DAQ (Data Acquisition) - converts analog signal into
digital data
Fuser Roll - a roll that essentially “fuses” the image to
the paper so it cannot be altered. Found in the Xerox
iGen line of printers
iGen -Xerox iGen Digital Press. Production color
printer manufactured by the Xerox Corporation
LabVIEW - a graphical programming environment
used by millions of engineers and scientists to develop
sophisticated measurement, test, and control systems.
Developed in 1986 by National Instruments
Corporation
Solidworks - a 3D CAD Software package that
includes simulation tools. SolidWorks is a Dassault
Systémes S.A. brand.
Xerox Corporation – headquartered in Norwalk, CT,
it is the world’s leading enterprise for business process
and document management
Figure 1: Schematic of Fuser Roll Assembly
BACKGROUND
Xerox Corporation approached our group to help them
with a solution to a bearing problem they were
experiencing in their iGen printers. As the fuser rolls
come back for remanufacturing every 200,000 prints,
Xerox Corporation had no way of telling if the
bearings were able to be reused. As a result, many
bearings that could have been reused were scrapped,
leading to wasted money and resources. The team’s
goal in this experiment was to design and run a fixture
that can characterize the life of the bearing under the
conditions seen in the printer. These conditions were
given to us by the members at Xerox Corporation.
The bearing experiences an external temperature of
230°F while operating, as well as an axial load of 360
lbs. The outer race is fixed, while the inner race is
spinning at 79.8 revolutions per minute.
Using these conditions, the team was told to design a
fixture that could put the bearing under the given
conditions as seen in the printer. Because a fixture
like this was not in Xerox Corporation’s possession,
the team used the help of Dr. Stephen Boedo, and his
expertise in bearings. Dr. Boedo has done a lot of
research in the field of bearings, and has published
many papers on this subject. With the support of the
Xerox Corporation, alongside the help of Dr. Boedo,
the group had to come up with a way to characterize
the life of the bearing.
bearing, how to spin the bearing, etc. After the ideas
were written down, the team then came up with four
different options that could be feasible. From there, a
Pugh Selection Matrix was created and used to
compare the different setups. In the end, the team
chose to look at each option and take the best parts and
compiled them into the final fixture setup.
The final design had the following characteristics:
- Fixed outer race
- Pneumatic loading
- DC motor
- Belt driven shaft
- Conduction to outer race
- Accelerometer for measuring vibration
- Thermistor for controlling heat
- Microcontroller
- LabView interface
With this information we were able to draw up a crude
initial design with pencil and paper:
DESIGN PROCESS
- Project Specifications
A list of specifications was created by the group and
supported by the customer before concept generation
started. This ensured that the group and the customer
were on the same page as to what was being designed
and built. These specifications included loading
conditions, error of measurements, as well as
measurement specifications.
Engineering Specs
Engineering Metrics
Measurement of Torque
Measurement of Vibration
Measurement of Acceleration
Measurement of Temperature
Error of Measurements
Time to Take Measurements
Applied Load
Applied Temperature
Frequency
Units
in-lb
g
g
°F
%
s
lb
°F
RPM
Figure 2: Concept drawing of the fixture
Technical Targets
TBD
TBD
TBD
TBD
< 5%
TBD
360lb
230°F
79.8RPM
Table 1: Engineering Specifications
*Unfortunately, cost of the torque meter was over-budget, and this
metric was consequently eliminated from the final assembly.
- Concept Generation
The team started the design of the fixture by using a
whiteboard to come up with ideas on how to achieve
the specifications set forth by the Xerox Corporation.
This included how to load the bearing, how to heat the
- CAD Design
Refined construction of the fixture design was
completed using SolidWorks. This software package
allowed the team to quickly and accurately model the
whole fixture assembly. It also allowed for quick
changing of dimensions as the assembly process took
place.
required the need to calculate the new pressure needed
for 360 lb.
𝐴 = 𝜋 ∗ 𝑟 2 = 𝜋 ∗ 1.52 = 7.069𝑖𝑛2
Equation 3: Area of 3.00 in bore pneumatic cylinder
𝐹 = 𝑃 ∗ 𝐴 → 360𝑙𝑏 = 𝑃 ∗ 7.069𝑖𝑛2 → 𝑃 = 50.9𝑝𝑠𝑖
Equation 4: New pressure for 360 lb with 3.00 in bore
Because the pneumatic cylinder did not need a long
stroke to load the bearing, the Parker “pancake style”
pneumatic cylinder was chosen. It has a 3.00 in bore
with 1.00in stroke, and comes in just under 3 inches
tall. The connector has a 5/8”-18 female connector,
for which we bought a 5/8”-18 rod to connect to.
Figure 3: Final proposed design of fixture
SolidWorks enabled the team to see what the fixture
would look like, and how it all fit together. Not shown
above is the pneumatic setup, only pictured is the
pneumatic cylinder. Also missing from this CAD
assembly is the electronic components and other
various pieces of hardware that will work together to
make the fixture run.
The accelerometer can be seen attached to the top of
the upper shoe, with the bearing sandwiched between
the two shoes. The lower shoe is supported by the
“pancake style” pneumatic cylinder, and is allowed
motion up and down only by the guide rails on either
side. Further down the shaft, the support bearings help
to hold the shaft level, as well take the force of the
moment created from the pulley at the end of the shaft.
The motor is not connected directly to the shaft
because the team wanted to isolate the vibrations
caused by the motors as best as possible, so Dr. Boedo
suggested that a belt be used to drive the shaft.
- Pneumatic Loading
The team decided to load the bearing via a pneumatic
cylinder that pushes up on the bottom shoe that
surrounds the bearing. Some formulas were used to
calculate the size of the pneumatic cylinder, as well as
what pressure was needed. The pressure coming out
of the wall was 70 psi, so the design intent was to stay
below this to ensure the bearing would see a
continuous load of 360 lb.
𝐹 = 𝑃 ∗ 𝐴 → 360𝑙𝑏 = 70𝑙𝑏⁄𝑖𝑛2 ∗ 𝐴 → 𝐴 = 5.142𝑖𝑛2
Equation 1: Area of cylinder needed for 70psi
𝐴 = 𝜋 ∗ (𝐷 ⁄2)2 → 5.142𝑖𝑛2 = 𝜋 ∗ (𝐷 ⁄2)2 → 𝐷
= 2.559𝑖𝑛
Equation 2: Diameter of cylinder needed for 70 psi
Because the team wanted to stay under the 70 psi, a
3.00-inch bore pneumatic cylinder was chosen. This
Figure 4: Parker Hannifin “pancake style” pneumatic
cylinders
To compliment the pneumatic cylinder, a solenoid
valve was also purchased. Because the pneumatic
cylinder is double actuating (which means it uses air to
extend as well as return), a 4-way/2-pos valve was
needed. This will be controlled via LabView. Also
included in the pneumatic setup is a semi-precision
dial regulator, so that the pressure can be regulated to
the 50.9 psi needed to load at 360 lb. Lastly, a
filtration system was necessary to keep debris that
might be present in the air supply from getting in the
cylinder. The system is plumbed with thermoplastic
tubing and push-to-connect fittings for easy
installation.
- Driving the Shaft
A large number of bearings will need to be tested for
the customer to get the data they require. The team
wanted to make sure that the fixture would not fail due
to fatigue. The main area of concern was moment
created by the alternating load created by the
pneumatic cylinder.
𝑀 = 1.847 𝑖𝑛 ∗ 361 𝑙𝑏 = 666.707 𝑖𝑛 𝑙𝑏
Equation 5: Largest moment generated by the shear
stress.
𝑀𝑐 666.707 𝑖𝑛 𝑙𝑏 ∗ 1.25 ∗ 64
=
= 3478.760𝑝𝑠𝑖
𝐼
2𝜋 ∗ (1.25)4
Equation 6: Stress created by the largest moment.
𝜎=
The max stress for infinite life of 1045 Steel was
calculated to be 5515.56 psi making for a factor of
safety of 1.585 for infinite life.
𝑆𝑢𝑡 = 81900𝑝𝑠𝑖
𝑆𝑒′ = .5𝑆𝑢𝑡
𝑆𝑒 = 𝑆𝑒′ 𝐾𝑎 𝐾𝑏 𝐾𝑐 𝐾𝑑 𝐾𝑒 𝐾𝑓−1 = 5515.56 𝑝𝑠𝑖
Equation 7: Maximum stress for infinite life.
−.265
𝐾𝑎 = 2.7 ∗ 𝑆𝑢𝑡
𝑀𝑎𝑐ℎ𝑖𝑛𝑒 𝐹𝑖𝑛𝑖𝑠ℎ
𝐾𝑏 = 1 𝐵𝑒𝑛𝑑𝑖𝑛𝑔
𝐾𝑐 = 1 𝐵𝑒𝑛𝑑𝑖𝑛𝑔
𝐾𝑑 = 1 𝑁𝑜𝑟𝑚𝑎𝑙 𝑇𝑒𝑚𝑝𝑒𝑟𝑎𝑡𝑢𝑟𝑒 ∗
*A factor of 1 was used even though the shaft could be
seeing temperatures of up to 230°F because at that
temperature Kd would be greater than 1.
Figure 5: SolidWorks Simulation results – No barrier
A thermal simulation was performed in SolidWorks to
determine if the heater was adequate to heat the
bearing up to 230 degrees. The simulation determined
that this heater would work, but it must be isolated in
some way from the bearing shoes to avoid acting as
heat sync, robbing the temperature form the bearing
itself.
𝐾𝑒 = 1 𝑅𝑒𝑙𝑖𝑎𝑏𝑖𝑙𝑖𝑡𝑦 𝐹𝑎𝑐𝑡𝑜𝑟
𝐾𝑓 = 1 𝑁𝑜 𝑆𝑡𝑟𝑒𝑠𝑠 𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛
𝑆𝑒
= 1.585
𝜎
Equation 8: Factor of Safety
𝑁=
- Heating the Bearing
It was necessary to heat the bearing in the test fixture
to simulate accurate operating conditions in the iGen
machine. The team determined that the operating
temperature of the bearings in the iGen machine is
approximately 230 degrees Fahrenheit. Based on this
specification, an appropriate heating mechanism was
chosen.
The heater chosen for the project was a custom-build
Mica Band Heater from Nordic Sensors Industrial Inc.
It was configured in such a way that the heater sits
between the outer race of the bearing and the shoes
apply the load to the bearing. The heater was to be
attached to the bearing shoes with J.B. weld, which
was chosen due to its strong bonding capabilities, even
under very high temperatures. Choosing a 120 Volt
heater (line voltage) at the maximum available 60
watts. The heater interfaces with LabView to regulate
temperature.
Figure 6: SolidWorks Simulation results – With
barrier
A thermal resistant coating Zirconium dioxide was
selected for the shoes to prevent heat transfer from the
heater to the shoes. Unfortunately, time constraints
prevented the team from having the shoes coated.
NOTE: In the final iteration of the project, it was
decided to eliminate the heater. For more information,
please see the section entitled “Results and
Instructions.”
- LabView Interface
The entire assembly is controlled via a LabView
interface providing ease of use and a platform that is
industry standard. All signals are collected and sent
via a National Instruments DAQ that handles both the
analog inputs of two thermocouples and the digital
input of an encoder. The device allows LabView to
collect all the pertinent information on the system's
operating conditions and respond using the digital outs
on the DAQ. In terms of signal processing the
program will collect several time intervals and average
them to create a Fast Fourier Transfer (FFT). This FFT
graph will show the intensity of vibrations throughout
the frequency domain. From this any peaks can be
investigated and compared against the expect wear
signals. In addition to data processing the LabView
code enables automation of the system starting with
the operation of the motor and pneumatic cylinder.
This entire system will be handed over to Xerox
Corporation along with documentation on how to
operate it as well as notes on how to modify the code.
Figure 8: Comparison of Bearing Saddles
-Motor Coupling
Figure 7: LabVIEW Interface
A coupling was used on the motor shaft that allowed
both the pulley and encoder for the motor controller to
be used. This coupling caused a wobble in the motor
shaft that translated into a variable speed in the drive
shaft. The planned method of analyzing the vibration
data depended on the speed of the drive shaft to be
constant.
-Supporting the Shaft
RESULTS AND DISCUSSION
-Heating the Bearing
The band heater used did not have a uniform thickness
as expected. The thickness of the heater varied
between 0.200” and 0.250. This prevented a tight fit
between the bearing, saddle, and heater, which would
have adverse affects on the vibration data.
The sleeve bearings used to support the shaft turned
out to be unviable. The amount of friction created by
those bearings was much higher than anticipated and
the motor was unable to drive the shaft at any speed
while the bearing was under load. In addition to this,
the sleeve bearings were specified as press fitting onto
the shaft, which in actuality was a slip fit. This would
have caused excessive noise in the data.
Figure 9: Sleeve Bearings – Original Design
Figure 7: Mica Band Heater
As a result, the original sleeve bearings were switched
out with ball bearings, which allowed the motor to
turn at the appropriate speed.
As discussed previously, the coupling was not
adequately supported. This is an easily addressable
issue. A possible solution would be to add an
additional support bearing onto the motor shaft. This
bearing would not add any additional noise to the
recorded signal due to the isolation created by the belt
and pulley system.
Figure 10: Ball Bearings – Alternate Design
Isolating the bearing from the motor with a drive belt
worked as planned. The motor produces a lot of
vibration while running. The drive shaft experiences
almost none of that vibration due to the separation of
from the belt.
CONCLUSIONS AND RECOMMENDATIONS
The test fixture is unusable in its current state.
However, with simple modifications, the setup can be
utilized in a manner, which will benefit the customer
and their needs.
Since the band heater turned out to be a failure of a
product, the team has researched possible alternatives.
A cartridge heater was determined to be the most
promising alternative. Holes should be drilled into the
saddle to place the cartridge heaters to heat the entire
saddle to the desired temperature.
The team did not have the time required to properly
look into the bearings used to replace the support
sleeve bearings. The bearings must be checked to
ensure that they don’t have the same vibration
response as the bearing being tested or an alternative
to the ball bearing should be used.
REFERENCES
[1] V.L. Parnell, S. Boedo, M.H. Kempski, K.B.
Kochersberger, and M.H. Haselkorn Health
Monitoring of LAV Planet Gear Bushings Using
Vibration Signature Analysis Techniques
SAE 2007 Commercial Vehicle Engineering Congress
and Exhibition Rosemont, IL, October 29-November
1, 2007
SAE Paper 2007-01-4190
[2] Shigley, J.E., Mischke, C.R., and Budynas, R.G.,
2004, Mechanical Engineering Design. New York,
NY: McGraw-Hill.
ACKNOWLEDGMENTS
Figure 11: CIR Series Cartridge Heater
We would like to extend our appreciation to:
 The Xerox Corporation, specifically Melissa
Monahan and Erwin Ruiz, for their financial
support and use of their resources, both
physical and intellectual.
 William Nowak, for his guidance and
determination to get this project going and
keep it going when times got tough.
 Dr Stephen Boedo, for the first-hand
knowledge he provided, his assistance, and
his interest in our project.
 Mitten Corporation, for their one-off
pneumatic setup designed for this project.