Ball Bearings InformationDescriptionBall bearings are used to provide smooth, low friction motion in rotary applications. Ball bearings are able to provide high performance and long lifetime in order to transferthe load from the balls to the inner races. The balls have minimal contact with the inner and outer races due to their spherical shape and this allows them to spin smoothly.A disadvantage of ball bearings is that the balls can become "flattened" over time with too much pressure on the outer races leading to eventual failure. Therefore it is very important that the load ratings and other parameters are monitored regularly.

Thrust bearing. Image Credit: WikipediaPartsBall bearings are composed of four main parts:two rings (or races)the rolling elements (the balls), and the ball separator (retainer).Radial ball bearings and angular contact bearings have an inner and outer ring. Radial ball bearings and angular contact bearings are designed to support loads perpendicular to the axis of rotation, referred to as radial loads. The outer racemounts intoa housing and is stationary. This part also aids in the transfer of the radial load from the bearing to the housing.The inner race mounts ontoa rotating shaft andsupports and guides theshaft duringrotation.

Image Credit: Bright Hub EngineeringThe rolling elements carry the load and distribute it throughout the raceways.The rolling elements rotate around the inner race, but not at the same speed as the rotation of theinner race.The separator acts as a barrier between the balls preventing them from bumping into each other. Thurst bearings are designed to support loads parallel to the axis of ratation, referred to as axial loads. Thrust ball bearings have two rings of equal size.TypesBall bearing types include:Radial ball bearings - Radial ball bearings are designed to carry both radial and (light)axial (thrust) loads, while thrust ball bearings are designed for pure thrust loads only.How It's Made - Ball BearingsVideo Credit: NTN Bearing Corporation via YouTubeDeep groove - Radial, or deep groove bearings, can take radial and axial loads to varying degrees but are used when the primary load is in the radial direction. They consist of an inner ring, an outer ring, balls and sometimes a cage to contain and separate the balls.Angular contact - Angular contact ball bearings are designed such that a contact angle between the races and the balls is formed when the bearing is in use. The major design characteristic of this type of ball bearing is that one or both or the ring races have one shoulder higher than the other.In order for these bearings to function properly, they must be assembled with a thrust load.This loading (or preload) creates a line of contact (or contact angle) between the inner race, the ball and the outer race. The preload can be built into the bearing or created when the bearing is inserted into an assembly. The contact angle varies from 15 to 40 and is measured relative to a line running perpendicular to the bearing axis. Angular contact bearings are one-directional thrust bearings that can withstand heavy thrust loads and moderate radial loads.Thrust ball bearings - Thrust ball bearings are designed for pure thrust loads.These bearings can handle little or no radial loads. The rolling element can be a ball, needle, or roller. Slewing ring or turntable bearings can accommodate axial, radial and moment loads. They are not mounted in a housing or on a shaft, but instead are mounted directly to a seating surface. The inner and outer rings are supplied with mounting holes. The inner ring, outer ring, or both may have integral gears. These bearings are referred to as tabletop bearings, turntable bearings, and slewing rings.SpecificationsDimensionsImportant dimensions to consider when specifying bearings include:Bore - The bearing industry uses a standard number system forbearings with metric diameter bores. For bore sizes 04 and up multiplyby 5 to obtain the bore in millimeters. If the bore is a hex this refers to the dimension across the flats. If the bore is tapered this refers to the smaller diameter.Outside diameter - The outside diameter of the bearing includes the housing if a housed unit, but excludes the flange if a flanged bearing. The outer ring width is the overall width of the outside of the bearing.Overall width - The overall width of the bearing or bearing assembly includesthe locking collar, if present.Operating SpecificationsImportant operating specifications to consider when searching for bearings include rated speed, dynamic axial or thrust load, and dynamic radial load.The ratedspeed for a bearingrunning with grease lubricationis lower than a bearing with oil lubrication.The dynamic axial or thrust load is the calculated constantaxial load, which a group of identical bearings with stationary outer rings can theoretically endure for a rating life of 1 million revolutions of the inner ring.The dynamic radial load is the calculated constant radial load, which a group of identical bearings with stationary outer rings can theoretically endure for a rating life of 1 million revolutions of the inner ring.Bearing Load, Fatigue, and LifespanOptimum bearing life is obtained when the balls and raceways have absolute minimal surfacecontact supplemented with proper lubrication. Loads forball bearings are subject to static or dynamics loads, as well as axial or radial loads. This means four variables need to be accounted for to determine working loads for a bearing. Ballbearings can handle substantially more radial and dynamic loads than axial and static loads.The first sign of non-elastic deformation will be flattened spots on the balls, which will hinder rotation.Calculated life of a bearing is based on its load, operating speeds, and environmental factors. Industry standards typically require that 90% of bearings are still serviceable after 1 million rotations, and 50% of bearings still be serviceable after 5 million rotations. This is known as bearing fatigue life.An underestimate (for safety)of a bearing's lifespan, as well as the applicable variables to calculate such,is offeredwithEngineer's Edge online ball bearing fatigue life calculator.It can also be accomplished with the following formula:

Where:Bearing Life in hoursExtended Basic Dynamic Load Rating in Pounds or NewtonsDynamic Load Rating Adjustment Factor for Number of Adjacently Mounted BearingsLife Adjustment Factor for ReliabilityLife Adjustment Factor for Ball Bearing MaterialLife Adjustment Factor for Application ConditionsOperating Speed (rpm)Equivalent Radial Load on Bearing in Pounds or NewtonsMaterialsSpecial materials and plating options to consider for ball bearings include stainless steel, plastic, ceramic balls, ceramic races, and platings.Ball bearings are made oflargely through-hardened materials with a minimumRockwell ratingof 58 Rc. 440C stainless steel and SAE 52100 steel are the most common materials for raceway and ball designs, but these alloys are not suitable for operating or friction temperatures above 350 F. Forms of molybdenum steels are excellent for temperature resistance even over 1000 F.The shields and seals of a bearing do not carry a radial load and only light axial loads, if any. Metal shields are usually of the same material as the bearing raceways, but other common bearing face materials and their attributes are as follows:

Table credit: Bearing Specialist AssociatesStamped steel is the most common retainer material; stamped or machined bronze or brass and plastic (such as nylon) are also commonly available. These materials feature good temperature resistance in high-speed applications. Plastic retainers have a higher speed capabilityand are limited by temperatures, but plastic retainers for high-speed applications made of phenolic materials (270 F), PTFE (450 F), or polyimide (500 F) are available.ApplicationsSpecial applications for bearings include airframe or aircraft control, aerospace, agriculture, automotive, ball screw support, instrument or miniature, medical or dental, military, pump, spindle or super precision, and sporting and consumer goods.Airframe/ Aircraft ControlAircraft Control and Airframe Bearings are specially designed to meet the demands of aircraft control and aerospace applications. They can be of ball, roller, or needle roller construction. Most aircraft control and airframe bearings are manufactured to U.S. government military (MIL-SPEC) standards.

AerospaceBearings designed for aerospace applications such as jet engines and helicopters.

AgricultureBearings designed for agriculture equipment and environments.

AutomotiveBearings specially designed forthe automotive industry.

Ball Screw SupportThese bearings are specially designed for use in ball screw or lead screw applications. Most ball screw support bearings are angular contact bearings with a steep contact angle, such as 60, and are available in duplex, triplex and quadruplex configurations. Other designs include bearings containing separate thrust and radial roller bearings in a single assembly. Cartridge designs are also available that include a housing, seals, and bearings.

Instrument/ MiniatureInstrument and miniature bearings are small deep groove or angular contact bearings. They are used in applications requiring very small bearings, such as dental drills and computer disk drives.

Medical /DentalBearings specially designed formedicalor dental equipment.

MilitaryBearings manufactured in accordance with the U.S. Government standards as dictated by the appropriate military specifications.

PumpThese bearings aredesigned for the conditions found in pumps, including high loads, poor or degraded lubrication, and high operating temperatures.

Spindle / Super PrecisionThese are high precision bearings intended for use in machine tool spindles.

Sporting and Consumer GoodsBearings specially designed for the sporting and consumer goods market. Products in the sector include inline skates, skateboards, and fishing reels.

The simple design of ball bearings makes them ideal for many weightbearing applications. Specific applications include hard drives, roller skates, rotary actuators, and rail cars just to name a few. Ball bearings come in different sizes, are inexpensive, and require little to no maintenance.StandardsQuality radial ball bearings are subject to standards, which indicate their precision andefficiency. Bearing quality is rated by ABEC (Annular Bearing Engineers' Committee).These ratings classify different accuracy and tolerance ranges for ball bearings. The higher the ABEC number the tighter the bearing tolerances.Very high-speed applications will see the greatest benefit from a more precise bearing.A manufacturer does not have to follow theseindustrial guidelines.North American radial ball bearings are under edict of the ABEC scale, while other ball bearings adhere to ISO 492 or its regional equivalent (DIN, KS, etc.) There are five accepted levels of the ABEC/ISO 492 scale and the level is not related to the size of the bearing.Boca Bearings Inc.has atolerance charton the dimensional variances acceptablefor each ABEC/ISO standard, organized by bearing dimension.Some manufacturers may quote an ABEC rating not listed above. This is an inaccuracy; there are only five ABEC ratings.Ball bearings can be manufactured and tested using standards developed by a diverse range of societies and associations. ANSI -American National Standards Institute, AFBMA - Anti-friction Bearing Manufacturers Association specifies other standards and ISO - International Organization for Standardization also specify standards.MIL-STD-206- Friction torque testing for bearings.ABMA-STD-9 - Load ratings and fatigue life for ball bearings.ASTM D3336 - Standard testing method for life of lubricating greases in ball bearings at elevated temperatures.ReferencesTypes of Bearing - Ball BearingBearings 101Selecting a bearingBall Bearing OverviewImage Credits:ABT Bearing | Igus | Mechanical Design ForumRead user Insights about Ball Bearings

Related Products & Services Aerospace Bearings Aerospacebearings are designed to meet the rigorous demands of aircraft control and aerospace applications.Angular Contact Bearings Angular contact bearings are designed so that a contact angle between the races and the balls is formed when the bearing is in use.Insert Bearings Insertbearings andwide inner ring bearings mount to shafts via setscrews or locking collars.Miniature Bearings and Instrument Bearings Miniature bearings and instrument bearings carry moderate radial and thrust loads at low operating torque while providing high performance in a small envelope design. These types of bearings are single row ball bearings available in up to 1 1/8" outer diameter (OD) sizesNeedle Roller Bearings Needle roller bearings are a type of radial roller bearing with rollers whose length are at least four times their diameter. These bearings are valued for their high load capacityand low sectional height.Roller Bearings Roller bearings are used in rotary applications to replace sliding movement with low friction, rolling motion. The principal types of roller bearings are cylindrical, spherical, and tapered.Thin-section Bearings Thin-section bearings have small cross-sections with respect to their diameter.Supplier Datasheets View Suppliers by State Alaska Alabama Arkansas Arizona California Colorado Connecticut District of Columbia Delaware Florida Georgia Hawaii Iowa Idaho Illinois Indiana Kansas Kentucky Louisiana Massachusetts Maryland Maine Michigan Minnesota Missouri Mississippi Montana North Carolina North Dakota Nebraska New Hampshire New Jersey New Mexico Nevada New York Ohio Oklahoma Oregon Pennsylvania Rhode Island South Carolina South Dakota Tennessee Texas Utah Virginia Vermont Washington Wisconsin West Virginia Wyoming

View Datasheets by Spec Aerospace Agriculture Airframe/ Aircraft Control Angular Contact Ball Bearing Automotive Ball Screw Support Ceramic Balls Ceramic Races Instrument/ Miniature Mast Guide Bearing Medical /Dental Military Bearing Type:Other Special Application:Other Plastic Plated Pump Radial Ball Bearing Slewing Ring / Turntable Bearing Spindle / Super Precision Sporting and Consumer Goods Stainless Steel Thrust Bearing Related Products torrington bearing catalogue, mini ball bearings, isb bearing, double row ball bearing, bearings locking collar, deep groove ball bearings, thrust ball bearing, flanged ball bearings, military bearing, spring loaded ball bearings, bicycle ball bearings, spherical ball bearings, miniature turntable, surplus ball bearings, 4 inch bearing, ball bearing sleeve, motor bearing type, thin section ball bearings, ball bearing switch, friction pendulum bearing, large ball bearings, motor ball bearings, mounted ball bearings, nylon ball bearing, plastic ball bearing, rmb bearings catalog, steel ball bearings, 1/2 inch ball bearings, 3/8 inch bearing, 5/8 inch bearing HomeAbout IHS Engineering360Advertise With UsHow We Use CookiesFollow IHS Engineering360

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