Bearing Types

History of Inventions of Rolling Element Bearings

Primary Function of Bearings

• Transmit loads

• Reduce Friction

• Secondary roles– Support the shaft– Locate the shaft

Bearing Loads

How did a bearing evolve ?

* Invention of wheel

* Wheel rotates on axle

* Wear Plate + Rollers

* Inner ring + Outer ring

+ Rollers

* With introduction of

cage Rolling Bearing

was created

Roller and Ball Raceway Contact

Types of Rolling ElementsSpherical roller(asymmetrical)

Spherical roller(symmetrical)Ball

Taper roller

Needle roller

Cylindrical roller

Bearing Components(Deep Groove Ball Bearing)

Seal Rolling Elements Inner RingOuter ring Cage Seal

Characteristics

Deep grooveball bearing

Angular contactball bearing

Self-aligningball bearing

Ball bearings Point Contact :

* Less area of contact* Less friction* More speed * Less load

Cylindricalrollerbearing

Taperrollerbearing

Needlerollerbearing

Sphericalroller bearing

Roller bearingsLine Contact :

* More area of contact* More friction* Less speed * More load

Bearing Loads

Radial rolling bearings

Deep grooveball bearing

Angular contactball bearing

Self-aligningball bearing

Cylindricalrollerbearing

Taperrollerbearing

Needlerollerbearing

Sphericalroller bearing

Ball bearings Roller bearings

Radial rolling bearings

Thrust ball bearing

Ball bearings Roller bearings

Thrust bearings

Angular Contact Ball Thrust bearing

Taper Roller Thrust

bearing

Spherical Roller Thrust

bearing

Cylindrical / Needle Roller Thrust

bearing

Bore

Bore surface

O.D. surface

O.D.

Bearing Terminology

Inner ring raceway

Side faces

Inner ring land

Outer ring raceway Outer ring land

Bearing Terminology

Ball and Roller Bearing Ranges

Deep groove

Ball bearings Roller bearings+Angularcontact

Self-aligning Cylindrical Taper Needle Spherical

Load Capabilities

Load carrying capacityis expressed as the basicdynamic load rating

Relative Speed Limitations

Grease lubricationspeed rating

Oil lubricationspeed rating

r/min

Bearing Contact Angle

Single Cylindrical Angular Taper Spherical Row Roller Contact Roller Roller

Radial Loads Combined Loads

Bearing ComponentsOuter Ring

Inner Ring

Cage

Rolling Element

Closures: Shields

Non-Contact Seal

RZ

Land Riding Lip Seal

RS1

Rolling Bearings are Precision Products

1µ

How much is a µ?

Ahuman

hair

0,06 mmStandard

High precision bearing

Precision bearing

Normal

P6 P6SP

P4AUP

PA9APA9B

Toleranceclasses

0/-15 µm0/-12 µm

0/-9 µm 0/-7 µm0/-2,5 µm

Precision Classes Precision classes: US vis-a-vis Europe

ABEC ISO

1 Normal

3 P6

5 P5

7 P4

9 P9– Generally, use bearings no more than one

precision class better than the precision of the mating components

– Extra precision has no benefit if applied to poorly made mating components

Radialclearance

Axialclearance

Internal Clearances

Bearing Basics

C1 - Less than C2 clearance

C2 - less than normal clearance (CN, C0) - normal clearance (not generally marked)

C3 - greater than normal clearance (“standard”)

C4 - greater than C3 clearance

C5 - greater than C4 clearance

Example:

A 6210 /C3 Ball bearing has from 18 - 36 µm (microns) or 0.0007” - 0.0014” Radial Internal Clearance