Timken Engineering User Manual
TIMKEN ENGINEERING MANUAL
ENGINEERING MANUAL INDEX
TIMKEN OVERVIEW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
SHELF LIFE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
WARNINGS/DISCLAIMERS ..................................8
BEARING SELECTION PROCESS ..............................9
Bearing Types ..........................................10
Cages .................................................28
Determination of Applied Loads and Bearing Analysis .......32
Bearing Reactions ......................................39
Bearing Ratings ........................................47
System Life and Weighted Average Load and Life ..........55
BEARING TOLERANCES, INCH AND METRIC SYSTEMS .........56
Metric System .........................................57
Inch System ...........................................68
MOUNTING DESIGNS, FITTING PRACTICE,
SETTING AND INSTALLATION ..............................74
Tapered Roller Bearings .................................77
Spherical and Cylindrical Roller Bearings ..................82
Angular Contact Ball Bearings ...........................95
Radial Ball Bearings ....................................99
Precision Bearings ....................................109
FITTING PRACTICE TABLES ...............................126
Spherical Roller Bearings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Cylindrical Roller Bearings ..............................128
Radial Ball, Spherical and Cylindrical Roller Bearings ......132
Angular Contact Ball Bearings ..........................146
Radial Ball Bearings ...................................147
Tapered Roller Bearings ................................154
Precision Tapered Roller Bearings .......................168
Thrust Bearings .......................................180
OPERATING TEMPERATURES ..............................184
Heat Generation and Dissipation ........................187
TORQUE .................................................188
SPEED RATINGS ..........................................193
CONVERSION TABLES ....................................196
LUBRICATION AND SEALS .................................199
Lubrication ...........................................200
Seals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
TIMKEN ENGINEERING MANUAL
1
OVERVIEW
TIMKEN
GROW STRONGER WITH TIMKEN
Every day, people around the world count on the strength
of Timken. Our expertise in metallurgy, friction management
and mechanical power transmission helps them accelerate
improvements in productivity and uptime.
We supply products and services that can help keep your
operations moving forward, whether you need drive train
kits for commercial vehicles, durable housings for bearings
in dirty environments, couplings that avoid metal-to-metal
contact between motors and gearboxes, repair services for
bearings and gearboxes, roller chain for dry, abrasive and
high-moisture applications or other products and services for
your applications.
When you choose Timken, you receive more than high-quality
products and services: You gain a worldwide team of highly
trained and experienced Timken people committed to working
collaboratively with you to improve your business.
Globally, our 17,000 people provide reliable answers for a
wide range of operations in manufacturing, mining, medical
equipment, aerospace, transportation, oil and gas – and other
diverse industries.
2 TIMKEN ENGINEERING MANUAL
OVERVIEW
INCREASE YOUR EQUIPMENT UPTIME
In addition to high-quality bearings and mechanical power
transmission components, we provide valuable integrated
products and services. For example, we offer repair services
and equipment monitoring equipment that can alert you to
problems before they impact your uptime.
Additionally, we offer a broad selection of seals, premium
TIMKEN
lubricants, lubricators, couplings and chain to keep your
operations moving smoothly.
Our 12 technology and engineering centers in the United
States, Europe and Asia help pioneer tomorrow’s innovations
with extensive basic and applied scientific research programs.
Through internal development and strategic acquisition of
innovative companies, we continue to expand our portfolio
of highly engineered bearings, power transmission products
and advanced services.
TIMKEN ENGINEERING MANUAL
3
TIMKEN
INTRODUCTION
INTRODUCTION
Timken is a leader in the advancement of bearing
technology. Expert craftsmanship, well-equipped
production facilities, and a continuing investment in
technology programs ensure that our products are
synonymous with quality and reliability. Today, our
plants manufacture several bearing types over a
broad range of sizes.
Anti-friction bearings inherently manage broad ranges
of speed and many combinations of radial and thrust
loads. Other important environmental conditions, such
as low and high temperature, dust and dirt, moisture,
and unusual mounting conditions, affect bearing
operation.
This engineering section is not intended to be
comprehensive, but does serve as a useful guide in
bearing selection.
Where more complex bearing applications are involved,
your Timken engineer should be consulted. The following
topics are covered within this manual:
Bearing design types.
•
Cage design types.
•
Life analysis procedure.
•
Bearing tolerances.
•
Fitting practice and mounting recommendations.
•
Operating temperatures.
•
Speed ratings.
•
Lubrication recommendations.
•
Seal design options.
•
4 TIMKEN ENGINEERING MANUAL
HOW TO USE THIS CATALOG
HOW TO USE THIS CATALOG
We designed this catalog to help you find the Timken®
spherical roller bearing solid-block housed units best suited to
your specifications.
Timken offers an extensive range of bearings and accessories
in both imperial and metric sizes. For your convenience, size
ranges are indicated in millimeters and inches. Contact your
Timken engineer to learn more about our complete line for the
special needs of your application.
This publication contains dimensions, tolerances and load
ratings, as well as engineering sections describing fitting
practices for shafts and housings, internal clearances,
materials and other bearing features. It provides valuable
assistance in the initial consideration of the type and
characteristics of the bearings that may best suit your
particular needs.
TIMKEN
ISO and ANSI/ABMA, as used in this publication, refer to
the International Organization for Standardization and the
American National Standards Institute/American Bearing
Manufacturers Association.
TIMKEN ENGINEERING MANUAL
5
TIMKEN
SHELF LIFE AND STORAGE OF GREASE-LUBRICATED BEARINGS AND COMPONENTS
SHELF LIFE AND STORAGE OF
GREASE-LUBRICATED BEARINGS
AND COMPONENTS
To help you get the most value from our products, Timken
provides guidelines for the shelf life of grease-lubricated
ball and roller bearings, components and assemblies. Shelf
life information is based on Timken and industry test data
and experience.
SHELF LIFE
Shelf life should be distinguished from lubricated bearing/
component design life as follows:
Shelf life of the grease-lubricated bearing/component
•
represents the period of time prior to use or installation.
The shelf life is a portion of the anticipated aggregate design
•
life. It is impossible to accurately predict design life due to
variations in lubricant bleed rates, oil migration, operating
conditions, installation conditions, temperature, humidity and
extended storage.
Shelf life values, available from Timken, represent a
•
maximum limit and assume adherence to the storage and
handling guidelines suggested in this catalog or by a Timken
associate. Deviations from the Timken storage and handling
guidelines may reduce shelf life. Any specification or
operating practice that defines a shorter shelf life should be
used.
European REACH Compliance
Timken lubricants, greases and similar products sold in
standalone containers or delivery systems are subject to the
European REACH (Registration, Evaluation, Authorization
and Restriction of CHemicals) directive. For import into the
European Union, Timken can sell and provide only those
lubricants and greases that are registered with ECHA
(European CHemical Agency). For further information, please
contact your Timken engineer.
Timken cannot anticipate the performance of the grease
lubricant after the bearing or component is installed or placed
in service.
TIMKEN IS NOT RESPONSIBLE FOR THE SHELF LIFE
OF ANY BEARING/COMPONENT LUBRICATED BY
ANOTHER PARTY.
6 TIMKEN ENGINEERING MANUAL
TIMKEN ENGINEERING MANUAL
6
SHELF LIFE AND STORAGE OF GREASE-LUBRICATED BEARINGS AND COMPONENTS
STORAGE
Timken suggests the following storage guidelines for our
finished products (bearings, components and assemblies,
referred to as “products”):
Unless directed otherwise by Timken, products should be
•
kept in their original packaging until they are ready to be
placed into service.
Do not remove or alter any labels or stencil markings on the
•
packaging.
Products should be stored in such a way that the packaging
•
is not pierced, crushed or otherwise damaged.
After a product is removed from its packaging, it should be
•
placed into service as soon as possible.
When removing a product that is not individually packaged
•
from a bulk pack container, the container should be resealed
immediately after the product is removed.
Do not use product that has exceeded its shelf life.
•
Contact your local Timken engineer for further information
on shelf life limits.
The storage area temperature should be maintained
•
between 0° C (32° F) and 40° C (104° F); temperature
fluctuations should be minimized.
The relative humidity should be maintained below 60 percent
•
and the surfaces should be dry.
The storage area should be kept free from airborne
•
contaminants such as, but not limited to, dust, dirt, harmful
vapors, etc.
The storage area should be isolated from undue vibration.
•
Extreme conditions of any kind should be avoided.
•
Due to the fact that Timken is not familiar with your particular
storage conditions, we strongly suggest following these
guidelines. However, you may be required by circumstances
or applicable government requirements to adhere to stricter
storage requirements.
TIMKEN
A
Most bearing components typically ship protected with a
corrosion-preventive compound that is not a lubricant. These
components may be used in oil-lubricated applications without
removal of the corrosion-preventive compound. When using
some specialized grease lubrications, we advise you to remove
the corrosion-preventive compound before packing the
bearing components with suitable grease.
We pre-pack most housed unit types in this catalog with
general-purpose grease suitable for their normal applications.
It may be necessary for you to frequently replenish the grease
for optimum performance.
Be careful in selecting lubrication, however, since different
lubricants are often incompatible. You may order housed units
pre-lubricated with a specified lubrication.
When you receive a bearing or housed unit shipment, do not
remove products from their packaging until they are ready for
mounting so they do not become corroded or contaminated.
Store bearings and housed units in an appropriate atmosphere
so they remain protected for the intended period.
TIMKEN ENGINEERING MANUAL
7
TIMKEN
WARNINGS/DISCLAIMERS
WARNING
Failure to observe the following warnings could
create a risk of death or serious injury.
Proper maintenance and handling practices are critical.
Always follow installation instructions and
maintain proper lubrication.
Never spin a bearing with compressed air.
The rollers may be forcefully expelled.
DISCLAIMER
This catalog is provided solely to give you analysis tools and data
to assist you in your product selection. Product performance is
affected by many factors beyond the control of Timken.
Therefore, the suitability and feasibility of all product selection
must be validated by you.
Timken products are sold subject to Timken's terms and conditions
of sale, which include its limited warranty and remedy, which terms
may be found at www.timken.com/ termsandconditionsofsale.
Please consult with your Timken sales engineer for more
information and assistance.
Warnings for this product line are found in this catalog
and posted on www.timken.com/warnings
CAUTION
Failure to observe the following warnings could
create a risk of death or serious injury.
Remove oil or rust inhibitor from parts before heating,
to avoid fire and fumes.
NOTE
Mixing greases can result in improper bearing lubrication.
Always follow the specific lubrication instructions of your
equipment supplier.
NOTE
Product performance is affected by many factors beyond the control
of Timken. Therefore, the suitability and feasibility of all designs and
product selection should be validated by you. This catalog is provided
solely to give you, a customer of Timken or its parent or affiliates,
analysis tools and data to assist you in your design. No warranty,
expressed or implied, including any warranty of fitness for a particular
purpose, is made by Timken. Timken products and services are sold
subject to a Limited Warranty.
You can see your Timken engineer for more information.
Every reasonable effort has been made to ensure the accuracy
of the information in this writing, but no liability is accepted for
errors, omissions or for any other reason.
COMPLIANCE
To view the complete engineering catalog, please visit
www.timken.com. To order the catalog, please contact your Timken
sales engineer and request a copy of the Timken Engineering Manual
(order number 10424).
European REACH compliance Timken-branded lubricants, greases
and similar products sold in stand-alone containers or delivery
systems are subject to the European REACH (Registration, Evaluation,
Authorization and Restriction of CHemicals) directive. For import
into the European Union, Timken can sell and provide only those
lubricants and greases that are registered with ECHA (European
CHemical Agency). For further information, please contact your
Timken sales engineer.
The Timken Company products shown in this catalog may
be directly, or indirectly subject to a number of regulatory
standards and directives originating from authorities in the USA,
European Union, and around the world, including:
REACH (EC 1907/2006, RoHS (2011/65/EU), ATEX (94/9/EC),
'CE' MARKING (93/68/EEC), CONFLICT MINERALS
(Section 1502 of the Dodd-Frank Wall Street Reform and
Consumer Protection Act).
For any questions or concerns regarding the compliancy or
applicability of Timken products to these, or other unspecified
standards, please contact your Timken sales engineer or
customer services representative.
NOTE
Never attempt a press fit on a shaft by applying pressure
to the outer ring or a press fit in a housing by applying
pressure to the inner ring.
8 TIMKEN ENGINEERING MANUAL
Updates are made periodically to this catalog.
Visit www.timken.com for the most recent version of the
Timken Spherical Roller Bearing Solid-Block Housed Units Catalog.
BEARING SELECTION PROCESS
The first step in bearing selection is to identify the best bearing
type for the application. Each bearing type has advantages and
disadvantages based on its internal design. Table 1, on page
10, ranks the different bearing types on various performance
characteristics.
The next step is to assess the bearing size constraints
including the bore, outside diameter (O.D.) and width. This
is done by defining the minimum shaft diameter, maximum
housing diameter and available width for the bearing in the
application. At this point, bearings may be selected from the
manual that fit within the defined size constraints. Several
bearings with different load-carrying capacities may be
available that fit within the envelope.
The third step is to evaluate the known environmental
conditions and application requirements. Environmental
conditions include factors such as ambient temperature,
applied load, bearing speed and cleanliness of the environment
immediately surrounding the bearing. Application requirements
such as bearing fits, bearing setting, lubricant type, cage type
and flange arrangements are determined based on the speed,
temperature, mounting conditions and loading conditions
within the application.
BEARING SELECTION PROCESS
Lastly, bearing life calculations are performed that take into
account all of the environmental and application conditions.
If more than one bearing has been evaluated up to this point,
selection is based on the bearing that provides the best overall
performance for the application. A detailed explanation of this
analysis procedure is included in the following sections. For
assistance, contact your Timken engineer for a comprehensive
computer analysis of your bearing application.
To view more Timken catalogs, go
to www.timken.com/catalogs
for interactive versions, or to
download a catalog app for your
smart phone or mobile device
scan the QR code or go to
timkencatalogs.com.
TIMKEN ENGINEERING MANUAL
9
BEARING SELECTION PROCESS
BEARING TYPES
BEARING TYPES
Cylindrical roller bearingTapered roller bearing Thrust tapered roller bearing Thrust cylindrical roller bearing
Spherical roller bearing
Thrust spherical roller bearing
Radial ball bearing Thrust ball bearing Angular contact ball bearing
TABLE 1. RELATIVE OPERATING CHARACTERISTICS OF VARIOUS BEARING TYPES
Characteristic
Pure radial load Good Unsuitable Excellent Unsuitable Good Unsuitable Good Poor Fair
Pure axial load Good Excellent Unsuitable Good Fair Excellent Fair Excellent Good
Combined load Excellent Poor Fair Unsuitable Good Fair Good Poor Excellent
Moment load Excellent Poor Unsuitable Unsuitable Unsuitable Unsuitable Fair Poor Good
High stiffness Excellent Excellent Good Excellent Good Good Fair Good Good
Low friction Good Good Excellent Poor Fair Fair Excellent Good Good
Misalignment Poor Poor Poor Unsuitable Excellent Excellent Good Poor Poor
Locating position
(fixed)
Non-locating
position (floating)
Speed Good Good Excellent Poor Fair Fair Excellent Excellent Excellent
Tapered Roller
Bearing
Excellent Good Fair Fair Good Good Good Excellent Good
Good Unsuitable Excellent Unsuitable Good Unsuitable Good Unsuitable Good
Thrust Tapered
Roller Bearing
Cylindrical Roller
Bearing
Thrust Cylindrical
Roller Bearing
Spherical Roller
Bearing
Thrust Spherical
Roller Bearing
Radial
Ball Bearing
Thrust Ball
Bearing
Angular Contact
Ball Bearing
10 TIMKEN ENGINEERING MANUAL
RADIAL BALL BEARINGS
Although radial ball bearings are designed primarily to support a
radial load, they perform relatively well under thrust or combined
radial and thrust load conditions.
Deep-groove ball bearings, commonly called Conrad or nonfilling-slot bearings, are assembled by displacing the inner
ring relative to the outer ring and inserting balls into the space
between the rings. By this method, only slightly more than half
the annular space between the inner and outer rings can be filled
with balls. Thus, capacity is limited.
To increase capacity, a filling slot or notch can be cut into the
inner ring, permitting the insertion of balls. Once the balls have
been inserted, the slot is filled by an insert. The increased number
of balls increases radial load capacity, but thrust load capacity
is sacrificed because of the filling slot.
The non-filling-slot or Conrad bearing is designated by the suffix
K and the filling slot bearing is designated by the suffix W.
BEARING SELECTION PROCESS
BEARING TYPES • RADIAL BALL BEARINGS
BALL BEARINGS WITH SNAP RINGS (WIRELOC)
Single-row radial ball bearings, including those with seals or
shields and open and shielded double-row types, are available
with snap rings. The snap ring protrudes from a groove in the
outer ring and acts as a shoulder to maintain bearing position. It
is designed for mounting in through-bored housings. This feature
is designated by adding the suffix G to the standard bearing
number. Single-shielded or sealed bearings with snap rings can
be supplied with the snap ring on the same side or opposite the
shield or seal position.
These bearings are advantageous in automobile transmission
design and in all applications where compactness is essential,
or where it is difficult and costly to machine housing shoulders.
The snap ring provides an adequate shoulder for the bearings
without a sacrifice in bearing capacity. The thrust capacity of the
snap ring in shear exceeds the thrust capacity of the bearing.
Typical designs illustrating how mounting simplification can be
accomplished through the use of snap ring bearings are shown
below.
Suffix K Suffix W
Conrad Filling Slot
Fixed mounting Floating mounting
Fig. 1. Typical mountings for radial ball bearings.
Fig. 2. Typical mountings for snap ring bearings.
TIMKEN ENGINEERING MANUAL
11
BEARING SELECTION PROCESS
BEARING TYPES • ANGULAR CONTACT BALL BEARINGS
ANGULAR CONTACT BALL BEARINGS
SINGLE-ROW
Single-row, angular contact ball bearings are designed for
combination loading with high thrust capacity in one direction,
and are suggested for applications where the magnitude of the
thrust component is high enough to preclude the use of radialtype ball bearings. They are dimensionally interchangeable with
single-row radial bearings of corresponding sizes.
The angular contact ball bearing has a relatively large contact
angle, high ring depths, and a maximum complement of balls
assembled through a counterbore in the outer ring. These
features provide bearings with significantly more thrust capacity
than radial bearings of the same size.
Angular contact bearings are used in such applications as gear
reducers, pumps, worm drives, vertical shafts and machine tool
spindles, where they are frequently mounted in various singlerow arrangements.
DOUBLE-ROW
Double-row, angular contact ball bearings are used effectively
where heavy radial, thrust or combined loads demand axial
rigidity of the shaft. This type is similar to a duplex pair of singlerow bearings by virtue of its two rows of balls and angular-contact
construction, which provide greater axial and radial rigidity than
can be obtained by using a single-row radial bearing.
With the exception of small sizes, double-row ball bearings are
made in the filling slot construction, and therefore, do not have
as much thrust capacity as equivalent size single-row, angular
contact bearings mounted in duplex pairs. Fixed and floating
mountings of double-row bearings are shown. Smaller sizes are
supplied with polymer retainers.
Fixed mounting Floating mounting
Fig. 4. Typical mountings for double-row,
angular contact ball bearings.
Fig. 3. Typical mounting for single-row, angular
contact ball bearings.
12 TIMKEN ENGINEERING MANUAL
BEARING SELECTION PROCESS
BEARING TYPES • PRECISION BEARINGS
PRECISION BEARINGS
(1)
MINIATURE AND THIN-SECTION
BALL BEARINGS
Timken produces precision ball bearings and assemblies
in miniature, instrument and thin-section series. All are
manufactured with quality steel, tolerances and features that
meet demanding application challenges. These precision
bearings and assemblies are found in surgical and diagnostic
imaging devices, precision pumps, measurement and material
handling equipment, as well as guidance, weapons and space
applications. Standard sizes range from 1 mm to 279.40 mm bore
(0.0250 in. to 11.000 in. bore).
Radial ball bearings
These Conrad bearings are available
in ISO P5/ABEC 5 to ISO P4/ABEC 7
precision levels as a standard catalog
offering. The deep-groove construction
allows for handling of radial, thrust or
combination loads. These are offered
primarily with 440C stainless-steel rings
and balls with one-piece fully machined
snap-in phenolic cages. In addition to
52100, other material and cage options
are available, as well as shields and
seals, and ceramic or titanium carbidecoated balls. Flanges are offered on miniature product. Typical
applications include guidance systems, medical (surgical
instruments and devices) and robotic joints.
Fig. 5. Radial ball
bearing.
Angular contact ball bearings
Angular contact ball bearings offer
maximum ball complement with a onepiece precision-machined retainer. The
increased ball complement, combined
with a relatively high contact angle,
maximizes axial stiffness. Angular
contact ball bearings are manufactured
to the same tolerances and standards
as the radial ball bearings. Rings and
balls are normally 440C stainless steel,
but other material options are offered.
Steel and ceramic balls are available
as standard. Typical applications use
preloaded pairs for maximum stiffness,
high speeds and precise positioning. These include surgical
handpieces, control moment gyros and other high-speed or highstiffness applications.
Fig. 6. Angular
contact ball bearing.
Fractured ring ball bearings
These bearings have outer rings
that are radially fractured in one
location. This permits the ring to be
opened for complete flexibility in the
choice of ball complement and cage
in a deep-groove radial bearing.
High-strength stainless-steel holding
bands are pressed on the ground
shoulders to retain tight abutment
and alignment of the fractured
surface during handling and normal
operation. Full complement and
retainer configurations are available.
Typical applications have a limited radial cross section and a
limited axial width. These applications require a bearing with
maximum radial capacity, as well as axial capacity in both
directions.
Fig. 7. Fractured ring
ball bearing.
Pivot ball bearings
Designed for space
constrained environments
where low torque is required,
pivot bearings use the mating
shaft for the inner raceway.
These bearings achieve
maximum power density with a
full complement of larger balls,
no cage or inner ring. Shields are available for the standard line.
Typical applications are in guidance systems, such as commercial
gyroscopes.
Fig. 8. Pivot ball bearing.
Thrust ball bearings
These bearings are designed for
applications where high axial
load, low speed and relatively high
torque are allowable. The standard
offering has all stainless steel
components for use where inert
materials are required. Stainless
steel allows operation as a fuel
control governor.
Fig. 9. Thrust ball bearing.
(1)
For additional information, refer to the Timken Super Precision Bearings for
Machine Tool Applications Catalog (order no. 5918) on www.timken.com.
TIMKEN ENGINEERING MANUAL
13
BEARING SELECTION PROCESS
BEARING TYPES • PRECISION BEARINGS
PRECISION BEARINGS – continued
TAPERED ROLLER BEARINGS
Timken’s high-precision tapered roller bearings consist of
carefully matched components that offer an added degree of
fine-tuning in the bearing setting and adjustment procedure to
maximize customer machine productivity. Timken manufactures
high-speed designs with a variable preload capability for optimum
performance. Timken also manufacturers Precision Plus bearings –
having an overall radial runout less than a single micron.
TS and TSF single-row bearings
These bearings are similar in design to the types described on
page 16. They are only produced in high-precision quality, to be
used in machine tool spindles, printing press cylinders and other
applications where accuracy of rotation is required.
TSHR - Hydra-Rib™ bearing with
preload adjustment device
For many applications, notably in
the machine tool industry, bearings
are required to run at high speeds
with a controlled preload setting. The
Hydra-Rib™ bearing has a floating
outer ring rib controlled by hydraulic
or pneumatic pressure, which ensures
that the required bearing preload is
maintained irrespective of the differential
expansions or changes in loading taking
place within the system.
Fig. 10. Hydra-Rib™
bearing.
TXR - crossed roller bearing
A crossed roller bearing is two sets of bearing rings and rollers
brought together at right angles with alternate rollers facing
opposite directions. TXR bearings have a section height not
much greater than that of a TS bearing. The steep angle, tapered
geometry of the bearing causes the load-carrying center of each
of the rings to be projected along the axis, resulting in a total
effective bearing spread many times greater than the width of
the bearing itself. This type of bearing offers a high resistance to
overturning moments.
The normal design of the bearing
is type TXRDO, which has a double
outer ring and two inner rings,
with rollers spaced by polymer
cages. Crossed roller bearings are
manufactured in precision classes.
Fig. 11. TXR crossed roller
bearing.
TXR
SUPER PRECISION BALL BEARINGS
The Timken line of super precision
machine tool ball bearings is designed
to meet ISO and ABEC tolerance levels.
However, Timken manufactures all
super precision ball bearings to surpass
ISO/ABMA criteria to ensure that the
end users receive only the highest
quality product to maximize machine
performance. Spindle bearings are the
most popular type of super precision
ball bearing used within the machine
tool industry. These angular contact
bearings are used primarily in precision, high-speed machine
tool spindles. Timken manufactures super precision machine
tool bearings in four metric ISO dimensional series. In addition,
because of specialized variations of bearing design and geometry,
Timken offers a total of seven angular contact bearing types within
these four basic series:
ISO 19 (9300WI, 9300HX series).
•
ISO 10 (9100WI, 9100HX, 99100WN series).
•
ISO 02 (200WI series).
•
ISO 03 (300WI series).
•
Multiple internal geometries are available to optimize either loadcarrying capacity or speed capability with part number suffixes
designated as: WI, WN, HX or K. WI-type bearings are designed to
maximize capacity of the various bearing cross sections and are
used in low to moderate speeds. The HX is Timken’s proven highspeed design. It has a significant advantage at higher speeds,
generating less heat and less centrifugal loading forces. The
WN-type is generally a compromise between the WI and HX as
it offers higher speed capability than the WI, but lower capacity,
higher stiffness and lower speed capability than the HX design.
Most of the bearing types are available in either 15 degree
(2MM) or 25 degree (3MM) contact angles. In addition, Timken
now stocks more ceramic ball sizes than ever for the highest
speed requirements. The K-type deep-groove (Conrad) super
precision radial ball bearing is generally used in applications
where capacity and stiffness do not require sets containing
multiple bearings. By virtue of the single-row, radial deep-groove
construction, and super precision level tolerances, these are
capable of carrying thrust loads in either direction. Also, they
Fig. 12. Super precision
ball bearing.
14 TIMKEN ENGINEERING MANUAL
BEARING SELECTION PROCESS
BEARING TYPES • PRECISION BEARINGS • BALL BEARINGS WITH LOCKING DEVICES
have a relatively high-speed capability – especially if a light axial
preload is applied. Timken offers deep-groove super precision ball
bearings in the following ISO dimensional series:
ISO 10 (9100K series).
•
ISO 02 (200K series).
•
ISO 03 (300K series).
•
For additional information, refer to the Timken Super Precision
Bearings for Machine Tool Applications Catalog (order number
5918) on www.timken.com. Or, contact your Timken engineer.
BALL BEARINGS WITH
LOCKING DEVICES
By virtue of their independent locking devices, these bearings
are suitable for mounting on straight shafting (no shoulders,
etc.). They are often supplied with spherical outer rings for selfalignment at mounting. Mounted alignment is usually required
because these bearings are generally assembled into pillow
blocks or flanged cartridges, or other housings bolted to pedestals
or frames independent of each other.
Easiest of all to install, wide inner ring ball bearings with selflocking collars are available in various sizes. These bearings,
shown with various seal and inner ring width variations, serve
many purposes in farm and industrial applications.
SETSCREW SERIES BEARINGS
The GYA-RRB and the GY-KRRB series are extended inner ring and
wide inner ring type bearings with specially designed setscrews
to lock on the shaft. These bearings can be purchased so that
they can be relubricated. Positive contact land-riding R-Seals
provide protection against harmful contaminants and retain
lubricant. Extended inner ring bearings are used when space is
at a premium and overturning loads are not a problem. The wide
inner ring setscrew series is available when additional surface
contact on the shaft is a requirement for added stability.
Fig. 14. YA-RR series.
SELF-LOCKING (ECCENTRIC) COLLAR
Timken invented the eccentric self-locking collar to facilitate
mounting of wide inner ring bearings. The self-locking collar
eliminates the need for locknuts, lock washers, shoulders, sleeves
and adapters.
The locking collar has a counterbored recess eccentric with
the collar bore. This eccentric recess engages or mates with an
eccentric cam end of the bearing inner ring when the bearing is
assembled on the shaft.
The collar is engaged on the inner ring cam of the bearing. This
assembly grips the shaft tightly with a positive binding action that
increases with use. No adjustments are necessary. The collar
setscrew provides supplementary locking.
RA-RR series Shroud-seal KRRB series
extended inner ring wide inner ring
with locking collar with locking collar
CONCENTRIC COLLAR
Using the concentric collar, the bearing is locked to the shaft by
two setscrews, 120 degrees apart, tightened in the collar and
passing through drilled holes in the inner ring. These units are
suited for applications where space is limited and reversing shaft
rotation is encountered.
Fig. 15. GC-KRRB series.
Fig. 13. Self-locking (eccentric) collar.
TIMKEN ENGINEERING MANUAL
15
BEARING SELECTION PROCESS
BEARING TYPES • TAPERED ROLLER BEARINGS
TAPERED ROLLER BEARINGS
SINGLE-ROW BEARINGS
TS - Single-row
This is the basic and the most widely
used type of tapered roller bearing. It
consists of the inner ring assembly and
the outer ring. It is usually fitted as one
of an opposing pair. During equipment
assembly, single-row bearings can
be “set” to the required clearance
(endplay) or preload condition to optimize
performance.
TSF - Single-row,
with flanged outer ring
The TSF type is a variation on the basic
single-row bearing. TSF bearings have
a flanged outer ring to facilitate axial
location and accurately aligned seats in
a through-bored housing.
Fig. 16. Single-row
TS bearing.
Fig. 17. Single-row
TSF bearing with
flanged outer ring.
DOUBLE-ROW BEARINGS
TDO - Double outer ring
This has a one-piece (double) outer ring
and two single inner-rings. It is usually
supplied complete with a inner-ring
spacer as a pre-set assembly. This
configuration gives a wide effective
bearing spread and is frequently chosen
for applications where overturning
moments are a significant load
component. TDO bearings can be used
in fixed (locating) positions or allowed to
float in the housing bore, for example, to
compensate for shaft expansion. TDOCD
outer rings also are available in most
sizes. These outer rings have holes in the
O.D. that permit the use of pins to prevent
outer ring rotation in the housing.
Fig. 18. Double-row
TDO bearing.
TDI - Double inner ring
TDIT - Double inner ring with tapered bore
Both comprise a one-piece (double) inner ring and two single
outer rings. They are usually supplied complete with an outerring spacer as a pre-set assembly. TDI and TDIT bearings can be
used at fixed (locating) positions on rotating shaft applications.
For rotating housing applications, the double inner ring of type
TDI can be used to float on the stationary shaft. Type TDIT has
a tapered bore to facilitate removal when an interference fit is
essential, yet regular removal is required.
16 TIMKEN ENGINEERING MANUAL
TDI
Fig. 19. Double-row, double-inner-ring bearings.
TDIT
BEARING SELECTION PROCESS
BEARING TYPES • TAPERED ROLLER BEARINGS
TNA - Non-adjustable
TNASW - Non-adjustable with lubricant slots
TNASWE - Non-adjustable with lubricant
slots and extended back face rib
These three bearing types are similar to the TDO with a one-piece
(double) outer ring and two single inner rings. The inner ring
front faces are extended so they abut, eliminating the need for a
separate inner-ring spacer. Supplied with a built-in clearance to
give a standard setting range, these bearings provide a solution
for many fixed or floating bearing applications where optimum
simplicity of assembly is required.
Types TNASW and TNASWE are variations having chamfers
and slots on the front face of the inner ring to provide lubrication
through the shaft. Type TNASWE have extended back face ribs
on the inner rings which are ground on the O.D. to allow for the
use of a seal or stamped closure. These designs are typically
used on stationary shaft applications.
SPACER ASSEMBLIES
Any two single-row bearings (type TS) can be supplied as a
double-row, pre-set, ready-to-fit assembly by the addition of
spacers, machined to pre-determined dimensions and tolerances.
Spacer assemblies are provided in two types: "2S" and "SR". This
concept can be applied to produce custom-made double-row
bearings to suit specific applications. In addition to providing
a bearing that automatically gives a pre-determined setting at
assembly without the need for a manual setting, it is possible
to modify the assembly width to suit an application, simply by
varying the spacer widths.
2S
Fig. 21. Spacer assemblies.
SR
TNA TNASW TNASWE
Fig. 20. Double-row, non-adjustable bearings.
2S - Two single-row assembly
Often referred to as snap-ring assemblies, type 2S consist of
two basic single-row bearings (type TS). They are supplied
complete with inner-ring and outer-ring spacers to give a predetermined bearing setting when assembled. Type 2S have a
specified setting range to suit the duty of the application. They
have an inner-ring spacer and a snap-ring, which also serves as
the outer-ring spacer, to give axial location in a through-bored
housing.
SR - SET-RIGHT™ assembly
Type SR are made to a standard setting range, based on Timken’s
SET-RIGHT™ automated setting technique suitable for most
industrial applications. They have two spacers and an optional
snap-ring that may be used for axial location. Because both types
are made up of popular sizes of single-row bearings, they provide
a low-cost option for many applications.
TIMKEN ENGINEERING MANUAL
17
BEARING SELECTION PROCESS
BEARING TYPES • TAPERED ROLLER BEARINGS
TAPERED ROLLER BEARINGS – continued
There are three basic mounting arrangements for spacer
assemblies.
Type 2TS-IM (indirect mounting)
•
These consist of two single-row bearings with an inner-ring
and outer-ring spacer. In some applications, the outer-ring
spacer is replaced by a shoulder in the bearing housing.
Type 2TS-DM (direct mounting)
•
These consist of two single-row bearings, with inner rings
abutting and an outer-ring spacer. They are generally used
at fixed (locating) positions on rotating shaft applications.
Type 2TS-TM (tandem mounting)
•
Where combined radial and thrust load capacity is
required, but the thrust component is beyond the capacity
of a single bearing (within a given maximum O.D.), two
single-row bearings can be mounted in tandem.
Appropriate inner-ring and outer-ring spacers are supplied.
Consult your Timken engineer for the most effective
and economical solution.
2TS-IM
2TS-DM
Fig. 22. Basic spacer assemblies.
2TS-™
18 TIMKEN ENGINEERING MANUAL
PACKAGED BEARINGS
BEARING SELECTION PROCESS
BEARING TYPES • TAPERED ROLLER BEARINGS
PINION PAC
Fig. 23. Packaged bearings.
Pinion Pac
™
™
bearing
UNIPAC
™
UNIPAC-PLUS
™
The Pinion Pac™ bearing is a ready-to-install, pre-set and sealed
package consisting of two rows of tapered roller bearings
mounted in a carrier. It is custom designed for the final drive
pinions of heavy commercial vehicles. The package gives the
differential pinion builder considerable improvements in reliability,
ease of assembly and supply logistics.
™
UNIPAC
bearing
The UNIPAC-PLUS™ bearing is a ready-to-install, pre-set,
pre-lubricated and sealed double-row assembly with a flanged
outer ring. Originally designed for the high-volume needs of
passenger car wheels, the UNIPAC bearing now has wider
application in wheel hubs of heavy vehicles as well as in industrial
equipment.
The UNIPAC bearing provides improvements in reliability, ease
of assembly and supply logistics.
AP
™
bearing
AP
™
SP
™
The AP™ bearing is a self-contained assembly, made in a wide
range of sizes. It consists of two single inner rings, a counterbored
double outer ring, a backing ring, two radial seals, an end cap
and cap screws. The AP bearing is supplied as a pre-set, prelubricated and sealed package. It was originally designed for
railroad journals, but also is used in many industrial applications.
™
SP
bearing
Similar in concept to AP bearings, the SP™ bearing is designed
for rail journal bearing applications. The SP bearing type differs
from the AP bearing in that SP bearings are more compact in size
and are manufactured to metric boundary dimensions.
™
UNIPAC-PLUS
bearing
The UNIPAC-PLUS™ bearing is a ready-to-install, pre-set,
sealed double-row assembly with a flanged outer ring. It also is
lubricated for the reasonable life of the bearing. It is designed
for wheel applications subjected to moderate to heavy loading.
The UNIPAC-PLUS bearing provides advantages of improved
reliability, reduced weight and easier assembly.
TIMKEN ENGINEERING MANUAL
19
BEARING SELECTION PROCESS
BEARING TYPES • TAPERED ROLLER BEARINGS
HIGH-SPEED BEARINGS
TSMA - Single-row with axial oil
TSMR - Single-row with radial oil
Some applications require extreme high-speed capability where
special lubrication methods must be provided.
The TSMA and TSMR are single-row
bearings with provisions for lubrication of
critical roller-rib contact area to ensure
adequate lubrication at high speeds.
The TSMA concept works by capturing
oil in a manifold (attached to the inner
ring), which is then directed to the
rib-roller contact through holes drilled
axially through the large inner ring rib.
The TSMR functions in a similar manner
with the difference being that holes are
drilled radially from the inner ring bore
to the large rib face. Oil is captured in
a circumferential groove in the inner
ring bore. It is directed to the rib-roller
contact area through radial holes.
Fig. 24. TSMA bearing.
OTHER DOUBLE-ROW BEARINGS
Type TDIE - Extended double inner ring
Type TDIA - Extended single inner ring
These double-row bearings are designed for applications where
it is required to lock the loose-fitted inner ring to a shaft, with
provision also for effective closure or sealing. Typical applications
include pillow blocks, disc-harrow and similar agricultural
machinery shafts and line shafts.
Type TDIE is available in two forms – cylindrical bore with the
inner ring extended at both ends and provisions for setscrews
and locking collars at each end, or with an inherently self-locking
square bore – ideal for farm machinery applications.
Type TDIA is similar to type TDIE with a cylindrical bore. There
is a provision for a locking collar at one end only. The compact
configuration is suited to pillow blocks and similar applications.
On all types, the hardened and ground O.D. of the inner ring
extension provides an excellent surface for effective closure
or sealing.
Type TNASWH - Non-adjustable, heavy-duty,
double outer ring
Type TNASWHF - Non-adjustable, heavy-duty,
with flanged double outer ring
These are double-row bearing assemblies with two inner rings
and a one-piece outer ring, similar to type TNASWE listed in this
manual on page 17.
The outer rings have a heavy wall section (type TNASWH),
allowing the bearings to be used directly as steady rest rollers,
in sheet and strip levellers or, with a flange (type TNASWHF), as
a complete wheel assembly for use on rails.
The outer ring is extended at both ends and counterbored to
accept stamped closures. Contacting seals are available for
certain sizes. These bearings are typically supplied as a unit
assembly and are pre-lubricated.
TDIE TDIE (square bore)
Fig. 25. Other double-row bearings.
20 TIMKEN ENGINEERING MANUAL
TDIA
TNASWH
TNASWHF
BEARING SELECTION PROCESS
BEARING TYPES • TAPERED ROLLER BEARINGS
FOUR-ROW BEARINGS
Four-row bearings combine the inherent high-load, radial/thrust
capacity and direct/indirect mounting variations of tapered roller
bearings into assemblies of maximum load rating in a minimum
space. Their main application is on the roll necks of rolling mill
equipment.
All four-row bearings are supplied as pre-set matched assemblies,
with all components numbered to ensure correct installation
sequence.
Type TQO - Quad taper
Type TQOW - Quad taper with lubrication slots
These pairs of directly mounted bearings consist of two double
inner rings, two single and one double outer ring, with an innerring spacer and two outer-ring spacers. These types are used
on roll necks of low- and medium-speed rolling mills, applied to
the necks with a loose fit. When the fillet and/or filler rings do
not have lubrication slots, they are provided in the faces of the
bearing inner rings (type TQOW). Slots in the inner-ring spacer
permit lubricant to flow from the bearing chamber to the roll neck.
The inner-ring spacers also are hardened to minimize face wear.
Type TQITS
Type TQITSE
The main feature of these bearings is a tapered bore – the taper
being matched and continuous through the inner rings. This
permits an interference fit on the backup rolls of high-speed mills,
where a loose inner ring fit of a straight bore type TQO bearing
could result in excessive neck wear.
These four-row bearings consist of two pairs of indirectly
mounted bearings: two single and one double inner ring, four
single outer rings and three outer-ring spacers. The adjacent
faces of the inner-rings are extended so that they abut,
eliminating the need for inner-ring spacers. The indirect mounting
of the bearing pairs increase the overall effective spread of the
bearing, to give optimum stability and roll rigidity.
Type TQITSE is the same as TQITS, but has an extension to the
large bore inner ring adjacent to the roll body. This not only
provides a hardened, concentric and smooth surface for radial
lip seals, but also improves roll neck rigidity by eliminating a fillet
ring. This allows the centerline of the bearing to move closer to
the roll body. It also permits shorter and less costly rolls.
Fig. 26. Four-row
bearing assemblies.
TQO/ TQOW
Sealed roll neck
The sealed roll neck bearing is similar to the TQO. A specially
designed sealing arrangement is incorporated in the bearing
to endure highly contaminated environments. The special seal
design is built into the bearing to prevent ingress of contamination
from outside the bearing envelope and extend the useful
bearing life.
Fig. 27. Sealed roll neck
bearing.
TQITS TQITSE
Fig. 28. Four-row bearings with tapered bore.
SEALED BEARINGS
TSL
Timken offers a wide range of sealed
bearings such as the DUO-FACE
shown in fig 29. The TSL incorporates a DUOFACE PLUS seal, making it an economical
choice for grease-lubricated applications
at moderate speeds. See the SEALS section
in the back of this manual for additional seal
designs.
®
PLUS seal
Fig. 29. TSL sealed
bearing.
TIMKEN ENGINEERING MANUAL
21
BEARING SELECTION PROCESS
BEARING TYPES • THRUST BEARINGS
THRUST BEARINGS
Standard types of thrust bearings manufactured by Timken are
included in this section. Each type is designed to take thrust
loads, but four types (TVL, DTVL, TTHD and TSR) accommodate
radial loads as well. All types reflect advanced design concepts,
with large rolling elements for maximum capacity. In roller thrust
bearings, controlled-contour rollers are used to ensure uniform,
full-length contact between rollers and raceways with resultant
high capacity. Thrust bearings should operate under continuous
load for satisfactory performance.
Type TVB – Grooved-ring thrust ball bearing
Type TVL – Angular contact thrust ball bearing
Type DTVL – Two direction angular contact thrust ball bearing
Type TP – Thrust cylindrical roller bearing
Type TPS – Self-aligning thrust cylindrical roller bearing
Type TTHD – Thrust tapered roller bearing
Type TSR – Thrust spherical roller bearing
Type TTHDFL – V-flat thrust tapered roller bearing
Type TTVS – Self-aligning V-flat thrust tapered roller bearing
Type TTSP – Steering pivot thrust cylindrical roller bearing
ring is shaft-mounted. The stationary ring should be housed with
sufficient O.D. clearance to allow the bearing to assume its proper
operating position. In most sizes, both rings have the same bore
and O.D. The housing must be designed to clear the O.D. of the
rotating ring, and it is necessary to step the shaft to clear the
bore of the stationary ring.
Type TVL is a separable angular contact ball bearing primarily
designed for unidirectional thrust loads. The angular contact
design, however, will accommodate combined radial and thrust
loads since the loads are transmitted angularly through the balls.
The bearing has two hardened and ground steel rings with
ball grooves and a one-piece brass cage that spaces the ball
complement. Although not strictly an angular ball bearing, the
larger ring is still called the outer ring, and the smaller the inner
ring. Timken standard tolerances for type TVL bearings are
equivalent to ABEC 1 where applicable, but higher grades of
precision are available.
Usually the inner ring is the rotating member and is shaft mounted.
The outer ring is normally stationary and should be mounted with
O.D. clearance to allow the bearing to assume its proper operating
position. If combined loads exist, the outer ring must be radially
located in the housing.
THRUST BALL BEARINGS
Thrust ball bearings are used for lighter loads and higher speeds
than thrust roller bearings. Types TVB, TVL and DTVL are shown
in fig. 30.
Type TVB thrust ball bearing is separable and consists of two
hardened and ground steel rings with grooved raceways, and
a cage that separates and retains precision-ground and lapped
balls. The standard cage material is brass, but this may be varied
according to the requirements of the application. Timken
tolerances for type TVB bearings are equivalent to ABEC 1 where
applicable, but higher grades of precision are available.
Type TVB bearings provide axial rigidity in one direction and their
use to support radial loads is not suggested. Usually the rotating
Fig. 30. Thrust ball bearing types.
standard
Type TVL bearings should always be operated under thrust load.
Normally, this presents no problem as the bearing is usually
applied on vertical shafts in oil field rotary tables and machine
tool indexing tables. If constant thrust load is not present, it should
be imposed by springs or other built-in devices.
Low friction, cool running and quiet operation are advantages of
TVL bearings, which may be operated at relatively high speeds.
TVL bearings also are less sensitive to misalignment than other
types of rigid thrust bearings.
DTVL is similar in design to TVL except the DTVL has an additional
ring and ball complement permitting it to carry moderate thrust
in one direction and light thrust in the other direction.
DTVLTVLTVB
22 TIMKEN ENGINEERING MANUAL
BEARING SELECTION PROCESS
BEARING TYPES • THRUST BEARINGS
THRUST CYLINDRICAL ROLLER BEARINGS
Thrust cylindrical roller bearings withstand heavy loads at
relatively moderate speeds. Standard thrust bearings can be
operated at bearing O.D. peripheral speeds of 3000 fpm (15 m/s).
Special design features can be incorporated into the bearing and
mounting to attain higher operating speeds.
Because loads are usually high, extreme-pressure (EP) lubricants
should be used with cylindrical roller thrust bearings. Preferably,
the lubricant should be introduced at the bearing bore and
distributed by centrifugal force.
All types of thrust roller bearings are made to Timken Standard
Tolerances. Higher precision may be obtained when required.
Type TP thrust cylindrical roller bearings have two hardened
and ground steel rings, with a cage retaining one or more
controlled-contour rollers in each pocket. When two or more
rollers are used in a pocket, they are of different lengths and are
placed in staggered position in adjacent cage pockets to create
overlapping roller paths. This prevents wearing grooves in the
raceways and helps prolong bearing life.
Because of the simplicity of their design, type TP bearings are
economical. Shaft and housing seats must be square to the axis
of rotation to prevent initial misalignment problems.
THRUST SPHERICAL ROLLER BEARINGS
Type TSR
The TSR thrust spherical roller bearing design achieves a high
thrust capacity with low friction and continuous roller alignment.
The bearings can accommodate pure thrust loads as well as
combined radial and thrust loads. Typical applications are air
regenerators, centrifugal pumps and deep well pumps. Maximum
axial misalignment between inner and outer ring is ±2.5 degrees.
Fig. 32. Thrust spherical roller bearing, type TSR.
THRUST TAPERED ROLLER BEARINGS
Type TTHD
Type TTHD thrust tapered roller bearings have an identical pair
of hardened and ground steel rings with conical raceways and a
complement of controlled-contour tapered rollers equally spaced
by a cage. The raceways of both rings and the tapered rollers
have a common vertex at the bearing center. This assures true
rolling motion.
TP
TPS
Fig. 31. Thrust cylindrical roller bearings.
Type TPS bearings are the same as type TP bearings except one
ring is spherically ground to seat against an aligning ring, thus
making the bearing adaptable to initial misalignment. Its use
is not suggested for operating conditions where alignment is
continuously changing (dynamic misalignment).
TTHD bearings are well-suited for applications such as crane
hooks, where extremely high thrust loads and heavy shock must
be resisted and some measure of radial location obtained.
For very low-speed, heavily loaded applications, these bearings
are supplied with a full complement of rollers for maximum
capacity. For application review of the full complement type TTHD
bearing, consult your Timken engineer.
Fig. 33. Thrust tapered roller bearing, type TTHD.
TIMKEN ENGINEERING MANUAL
23
BEARING SELECTION PROCESS
BEARING TYPES • THRUST BEARINGS
THRUST BEARINGS – continued
TTC cageless
TTSP steering pivot
There are two basic types of Timken® tapered roller thrust
bearings designed for applications where the only load
component is thrust, TTC and TTSP. The TTC bearing uses a full
complement of tapered rollers without a cage and is used when
the speeds are slow. The TTSP bearing uses a cage and is wellsuited for the oscillating motion of steering pivot positions.
Type TTHDFL Type TTVS
Type TTHDSX Type TTHDSV
V-flat tapered roller bearings (TTHDFL and TTVS) combine the
best features of thrust tapered and cylindrical roller bearings,
offering the highest possible capacity of any thrust bearing of its
size. V-flat design includes one flat ring and the second with a
tapered raceway matching the rollers. The design was originally
developed to be screwed down in metal rolling mill applications
where the thrust loads commonly exceed one million pounds.
These bearings have exceptional dynamic capacity within a given
envelope and provide superior static capacity. They are used
inheavily loaded extruders, cone crushers and other applications
where a wide range of operating conditions are found.
TTSPTTC
TTVSTTHDFL
TTHDFL
Most sizes utilize cages with hardened pins through the center
of the rollers, allowing closer spacing of the rollers to maximize
capacity. Smaller sizes have cast-brass cages, carefully
machined to permit full flow of lubricant.
Self-aligning V-flat bearings (TTVS) employ the same basic roller
and raceway design, except the lower ring is in two pieces, with
the contacting faces spherically ground permitting self-alignment
under conditions of initial misalignment. TTVS bearings should
not be used if dynamic misalignment (changing under load) is
expected.
TTHDSV
Fig. 34. Thrust tapered roller bearings.
TTHDSX
24 TIMKEN ENGINEERING MANUAL
RADIAL SPHERICAL ROLLER BEARINGS
BEARING SELECTION PROCESS
BEARING TYPES • RADIAL SPHERICAL ROLLER BEARINGS
The principle styles of radial spherical roller bearings that Timken
offers are:
≤400 mm outer diameter: EJ, EM and EMB.
•
>400 mm outer diameter: YM, YMB, YMD and YP.
•
The newly redesigned Timken
higher load ratings, increased thermal speed ratings and reduced
operating temperatures compared to the previous offering.
In addition to these improvements, cage designs vary between
the different styles as noted below. See the cage section for
more details.
Style Cage Design
EJ Land-riding steel cage; one per row
EM / YM Roller-riding one-piece brass cage
EMB/YMB Land-riding one-piece brass cage
YMD Land-riding two-piece brass cage
YP Steel pin-type cage
EM/YM and
EMB/YMB
Fig. 35. Radial spherical roller bearings.
Most Timken spherical roller bearings are available with a
cylindrical bore as well as a tapered bore. Tapered bore bearing
part numbers are designated with a K suffix.
®
EJ, EM and EMB bearings offer
YMDEJ
YP
OPTIONAL FEATURES AVAILABLE WITH
TIMKEN SPHERICAL ROLLER BEARINGS
W33 lubrication groove and oil holes
A lubrication groove and three oil holes are provided in the
bearing outer ring as standard. This is designated by the W33
suffix. It eliminates the expense of machining a channel in the
housing bore for introducing lubricant to the bearing. This design
feature allows the lubricant to flow between the roller paths,
through a single lubrication fitting. The lubricant moves laterally
outward from the center of the bearing, reaching all contact
surfaces and flushing the bearing. To order, add the suffix W33
to the bearing number (e.g. 22216EMW33).
Bearings for vibratory applications
Timken offers specific spherical roller bearing designs for
vibratory applications. They are designated by the W800
modification code and made to a C4 clearance. Specify W800
when ordering. This design provides:
A lubrication groove on the outer ring with three lubrication
•
holes to facilitate bearing lubrication.
Extra-close running accuracy (P5) with high and low points
•
marked on the bearing.
Reduced bore and outside diameter tolerances.
•
Radial internal clearance is made in upper two-thirds of
•
C4 clearance range.
These bearings are available with either a cylindrical or tapered
bore.
A taper of 1:12 is standard except for 240, 241 and 242 series,
which have a taper of 1:30.
SERIES
239 230 240 231 241 222 232 213 223 233
Fig. 36. Radial spherical roller bearing series.
TIMKEN ENGINEERING MANUAL
25
BEARING SELECTION PROCESS
BEARING TYPES • RADIAL CYLINDRICAL ROLLER BEARINGS
RADIAL CYLINDRICAL ROLLER BEARINGS
STANDARD STYLES
Timken® cylindrical roller bearings consist of an inner and outer
ring, a roller-retaining cage, and a complement of controlledcontour cylindrical rollers. Depending on the type of bearing,
either the inner or the outer ring has two roller-guiding ribs. The
other ring is separable from the assembly and has one rib or
none. The ring with two ribs axially locates the position of the
roller assembly. The ground diameters of these ribs may be used
to support the roller cage. One of the ribs may be used to carry
light thrust loads when an opposing rib is provided.
The decision as to which ring should be double ribbed is normally
determined by considering assembly and mounting procedures
in the application.
Type NU has double-ribbed outer and straight inner rings. Type
N has double-ribbed inner and straight outer rings. The use of
either type at one position on a shaft is ideal for accommodating
shaft expansion or contraction. The relative axial displacement
of one ring to the other occurs with minimum friction while the
bearing is rotating. These bearings may be used in two positions
for shaft support if other means of axial location are provided.
Type NJ has double-ribbed outer and single-ribbed inner
rings. Type NF has double-ribbed inner and single-ribbed outer
rings. Both types can support heavy radial loads, as well as
light unidirectional thrust loads. The thrust load is transmitted
between the diagonally opposed rib faces in a sliding action.
When limiting thrust conditions are approached, lubrication can
become critical. Your Timken engineer should be consulted for
assistance in such applications. When thrust loads are very light,
these bearings may be used in an opposed mounting to locate
the shaft. In such cases, shaft endplay should be adjusted at
time of assembly.
Type NUP has double-ribbed outer and single-ribbed inner ring
with a loose rib that allows the bearing to provide axial location
in both directions. Type NP has a double-ribbed inner ring and
a single-ribbed outer ring with a loose rib. Both types can carry
heavy radial loads and light thrust loads in both directions. Factors
governing the thrust capacity are the same as for types NJ and
NF bearings.
A type NUP or NP bearing may be used in conjunction with type
N or NU bearings for applications where axial shaft expansion is
anticipated. In such cases, the N or NU bearing accommodates
the shaft expansion. The NUP or NP bearing is considered the
fixed bearing because the ribs restrict the axial movement of
the rolling element. The fixed bearing is usually placed nearest
the drive end of the shaft to minimize alignment variations in the
drive. Shaft endplay, or float, is determined by the axial clearance
in the fixed bearing.
Types NU, N, NJ, NF, NUP and NP conform to ISO and DIN
standards for loose rib rings (thrust collars) and typical industry
diameters over or under roller.
The cylindrical roller bearing part numbers are in accordance
with ISO 15. They are composed of four digits, the first two digits
identify the dimensional series and the last two digits of the part
number are the bore size divided by 5. In the dimensional series,
the first digit is the width series and the second is the diameter
(outer) series. The width series increase width in the sequence
8 0 1 2 3 4 5 6 7. The diameter series increase radial section in
the sequence 7 8 9 0 1 2 3 4.
Types having an R prefix are similar in construction to their N
counterparts. However, they were designed to conform to ABMA
standards.
Inch-size bearings are identified by the letter I in the part number.
RIU, for example, indicates an inch bearing while RU indicates
the equivalent style in metric dimensions.
NU, RIU, RU N, RIN, RN NJ, RIJ, RJ NF, RIF, RF NUP, RIT, RT NP, RIP, RP
Fig. 37. Radial cylindrical roller bearings.
26 TIMKEN ENGINEERING MANUAL
BEARING SELECTION PROCESS
BEARING TYPES • RADIAL CYLINDRICAL ROLLER BEARINGS
EMA SERIES
The Timken® single-row EMA series cylindrical roller bearings
incorporate a unique cage design, proprietary internal geometry
and special surface textures. These features help to improve
bearing performance and can help to improve uptime and reduce
maintenance costs.
The cage is a one-piece brass design with full-milled pockets.
It is a land-riding cage which, unlike traditional roller-riding
cages, minimizes drag on the roller elements. This reduces heat
generation and improves bearing life. The high cage rigidity
allows for more rollers than possible with other brass cage
configurations.
Proprietary profiles on the rings and/or rollers increase the ability
to handle heavier loads than competing designs.
Engineered processes for rings and rollers provide enhanced
surface textures, resulting in lower friction, lower operating
temperatures and longer bearing life.
EMA series bearings are available in types N, NU, NJ and NUP.
FULL-COMPLEMENT (NCF)
The full-complement (NCF) single-row bearings include integral
flanges on the inner and outer rings. These bearings also can
manage axial loads in one direction and permit small axial
displacements.
5200 METRIC SERIES
This series features enhanced radial load ratings due to its
internal design proportions. In this series, the outer ring is
double-ribbed and the inner ring is full-width with a cylindrical
O.D. The bearing also can be furnished without an inner ring
for applications where radial space is limited. When so used,
the shaft journal must be hardened to HRC 58 minimum, and the
surface finished to 15 RMS maximum. The W designation in the
suffix indicates the outer ring is provided. The inner ring also can
be furnished separately. The A prefix indicates that the inner ring
is furnished either separately or as part of the assembly.
The bearing is usually provided with a rugged stamped-steel cage
(S designation) and is land-riding on the outer ring ribs. The cage
features depressed bars, which not only space rollers evenly, but
retain them as a complete assembly with the outer ring. Cages
of machined brass (M designation) are available for applications
where reversing loads or high speeds might indicate their need.
Outer rings are made from bearing quality alloy steel. The inner
rings are deep-case hardened to accommodate the hoop stresses
resulting from heavy press fits.
The standard bearing is produced with radial internal clearances
designated as R6. Other internal clearances can be supplied upon
request. Proper roller guidance is assured by integral ribs and
roller end clearance control.
A-52xx-WS A-52xx-WM
52xx-WS A-52xx
Fig. 38. 5200 metric series bearings.
TIMKEN ENGINEERING MANUAL
27
BEARING SELECTION PROCESS
CAGES • TAPERED ROLLER BEARING CAGES
CAGES
Cages (also referred to as rolling element retainers) serve several
purposes in the proper operation of a rolling element bearing.
Cages separate the rolling elements and prevent rolling element
on rolling element contact and wear. Cages align the rolling
elements on the inner ring to prevent rolling element sliding,
skidding, and skewing to facilitate true rolling motion. For handling
purposes, cages retain the rolling elements on the inner ring
assembly to allow for bearing installation. In some instances,
cages also improve flow of the lubricant to the bearing raceway
or rib contacting surfaces.
The following sections discuss the common types of cages
used for each major bearing design type (tapered, cylindrical,
spherical, and ball bearing). The basic design geometry, material,
and manufacture are discussed for each cage type.
TAPERED ROLLER BEARING CAGES
STAMPED-STEEL CAGES
The most common type of cage used for tapered roller bearings
is the stamped-steel cage. These cages are mass produced
from low-carbon sheet steel using a series of cutting, forming
and punching operations. These cages can be used in high
temperature and harsh lubricant environments.
POLYMER CAGES
Cages for tapered roller bearings made of polymer material are
used primarily for pre-greased and sealed package designs. The
most common polymer materials used are Nylon thermoplastics
with glass reinforcement. Polymer cages can be mass produced
in large quantities and offer more design flexibility than stampedsteel types. Polymer cages are lightweight and easy to assemble.
In some instances, increased bearing rating can be achieved
by allowing one or two extra rollers in the bearing complement.
Care should be exercised when using aggressive lubricants with
EP (extreme-pressure) additives in combination with elevated
temperatures greater than 107° C (225° F).
MACHINED CAGES
Machined cages for tapered roller bearings are robust in design
and are suited for high-speed and high-load applications.
Machined cages use alloy steels and are produced through
milling and broaching operations. Assembly does not require
a close-in operation and rollers can be retained using nibs or
staking. Oil holes also can be easily added for extra lubrication
for demanding applications. Some designs are silver plated for
special applications.
Fig. 39. Stamped-steel cage.
PIN-TYPE CAGES
Tapered roller bearing pin-type cages retain the rolling elements
by the use of a pin located through an axial hole in the center of
the roller. Pin-type cages for tapered roller bearings consist of
two rings with roller pins attached by screw threads at one end
and welding at the other end. These types of cages are primarily
used for larger tapered roller bearing designs (greater than
400 mm [15.7480 in.] O.D.). Pin-type cages are machined out
of steel and typically allow for an increased number of rolling
elements. Pin-type cages are restricted to low-speed applications
(less than 20 m/sec [4000 ft/min] rib speed).
TIMKEN ENGINEERING MANUAL
28
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