Skf Roller Bearing Handbook.pdf 33071

SKF INDUSTRIES, INC BEARINGS GROUP

.

SKF Industries Inc 1979 Although care has been taken to assure the accuracy of the data complied in this publication SKF does not assume any liability for errors or omsslons

t

REG NO. 47

Contents The History of Rolling Bearings . . . . . . . . . 2 Bearing Rolling

Nomenclature Bearing

.

Types

. .

. .

. .

. .

D

.

.

.

.

.

.

4

.

e

.

.

.

D

5

Bearing Types and their Function . . . . . . . . 6 Mounting of Bearings-Shaftsand Housings . . . . . 9 Do’s and Don’ts for Bearings . . . . . . . . . 14 Troubleshooting

.

.

D

,

O

s

a

r

.

.

.

O

.

19

SKF Industries, Inc. periodically conducts “Bearing Maintenance Seminars” at the Corporate Headquarters in King of Prussia, Pa. For information your local authorized SKF Distributor or SKF Sales Office.

THE HISTORY OF ROLLING BEARINGS THE

BASIC

developed

PRINCIPLES for

one

of

design

purpose

and

application

only--to

History records that down through the but not always achieved. Regardless object

sometimes

made

it

lessen

of

roiling

bearings

were

conceived

many

centuries

ago.

They

were

friction.

ages men desired to move heavy objects across the earth’s surface, Desired, of available manpower, sliding friction between the earth’s surface and the

impossible.

As far back as 1 100 B.C., we know that such friction was reduced by the insertion of rollers between the object and the surface over which it was being moved. Fig. 1 illustrates how, in 1 100 B.C., the Assyrians

and

Babylonians

used

rollers

to

move

enormous

stones

for

their monuments and palaces. Throughout history are recorded many similar examples of man’s war on friction.

In modern times, the first important victory over friction was the invention of the wheel. However, the early wheel was based on sliding friction (Fig. 2) and a long time elapsed before this principle was refined. Later, wheels rendered friction a “body blow” when they were rested on an assembly of balls or rollers. Cycling and Fig. 1 -Anti-fricfion

odoptafion,

I IO0 B C

--

skating, which involved personal effort, boosted interest in rolling bearings (Fig. 3)-and started long years of slow development.

Anyone who has tried to move a heavy object by sliding, readily appreciates the ease with which it can be done when rollers are used. Weight of the object is not a factor-as long as both the rolling elements and the surface over which they can it without being pressed out of shape.

Place a heavy book on a flat, smooth surface (Fig. 4) and as you push it across that surface, notice the amount of effort required. This is sliding friction. Fig. 2-Early wheel, based

on sliding friction

Fig. 3-Cycling boosted anti-friction interest

2

Fig. 4-Sliding

friction

Fig. S-Rolling motion

Now, place two round pencils under the book (Fig. 5). Note how easily it can be moved. This is the difference between sliding friction and rolling

motion.

You will note that, when pushing the book with the pencils as rolling elements, a tracking effect is present. The book can go forward or backward with ease.

Now, substitute several balls for the rollers (Fig. 6),

and note the

added ease with which the book moves. Also, note the fact that it Fig. 6-Improved rolling motion

can be moved in one direction as easily as in another. These advantages are due to point provided by the balls, rather than the line of the pencils.

In review - we noted that sliding the book on the surface required a certain effort - that rolling it over the pencils required less effort but that the direction was limited - and finally, when we substituted the balls, less effort was required and direction was unlimited.

The book, the surface and the pencils or balls are the three important, basic parts of a ball or roller bearing.

Fig. 7--Book becomes inner ring

If you performed this interesting experiment, you noted several important factors. First, that the book would run off the pencils and the balls. Second, and this may not have been so apparent, that there was a tendency for one

roiling element not to follow or “track”

the same as the other rolling element. This was true of both pencils and balls - but to a lesser degree in the bail experiment.

Let us imagine that the book in Fig. 6 is curled into the position of Fig. 7. The book is then the equivalent of the inner ring of a ball . bearing.

brl-------...._- - ----A Fig. 8-Surface

becomes outer ring

While our imagination is at play, picture the table surface of Fig. 6 curled into the position of Fig. 8 - and the balls in the position illustrated.

Actually, we have converted our early experiment into a basic ball bearing in design. The book becomes the inner ring - the surface the outer ring - and the balls the rolling elements (Fig. 9).

This

experiment,

however,

does

not

illustrate

one

other

important

part of a bearing. You will recall that we noted that the pencils or balls did not “track” - i.e., roll in the same direction, or keep the same distance apart. For this reason the bearing requires a cage, or retainer, to keep the rollers or balls in their proper position. In tapered roller bearings the inner ring is called the cone, - the Fig. 9--Experiment illustrates bask bearing design

outer ring, the cup.

3

BEARING NOMENCLATURE The illustrations below identify the bearing parts of the eight SKF basic bearing types. The used conform with the terminology section of the AFBMA* Standards+nd are mutually accepted by the anti-friction bearing manufacturers *Anti-Friction

Bearing

Manufacturers Association, Inc.

Self-Aligning Ball Bearing

Single Row Deep Groove Boll B e a r i n g

Double Row Deep Groove Ball Bearing

Spheric01 Roller Bearing

Angular Boll Bwring

Cylindrkol Roller horing

Tapered Roller Beoring

E Type Spherical Roller

Thrust Spheric01 Roller Thrust Bearing

1. 2. 3. 4. 5.

Inner Ring Inner Ring Corner tnner R i n g Loud Outer Ring Land Outer Ring

6 . Ball 7. Counter Bore 8. Thrust Face

4

9. 10. 11. 12. 13.

Outer Ring Raceway Inner Ring Raceway Outer Ring Corner Spherical Roller Lubrication Feature (Hole and Groove) (W33) 14. Spherical Outer Ring Raceway 15. Floating Guide Ring 16. Inner Ring Face

17. 18. 19. 20. 21. 22. 23. 24.

Outer Ring Face Cylindrical Roller Outer Ring Rib

Cone Front Face Cone Front Face Rib Cup (Outer Ring) Tapered Roller Cone Rock Face Rib

25. Cone Bock Face

2 6 . Under Cut 27. 28. 29. 30. 31. 32. 33.

Cone (Inner Ring) cage Cage Face Cage Guide Sleeve Shaft Washer (Inner Ring) Housing Washer (Outer Ring)

ROLLING BEARING TYPES BALL BEARINGS

Single Row

ROLLER BEARINGS

Radial Thrust

Double Row

Separable Outer Ring

Duplex

Snap Ring and Shield

Shield

Cylindrical Roller Separable Inner Ring

Magneto

Front

Tapered Roller

Seal

Multi-Row

Self-Aligning

Cylindrical Roller Nonseparable

Cylindrical

Roller

Wheel

.Spherical Roller Thrust

Spherical Roller Double Row

Needle Roller

5

BEARING TYPES AND THEIR FUNCTIONS Designers have a wide variety of bearing types from which to choose. Each bearing type has characteristics which make it the best choice for a certain application. The original selection is made to assure maximum bearing performance. Therefore, a replacement should be made with the same type bearing, of each bearing type will aid you to better serve your replacement field.

SELF-ALIGNING The

Self-aligning

BALL Ball

The

following resum’e of the functions

BEARINGS

Bearing,

with two rows of balls roiling on the spherical

surface of the outer ring, compensates for angular misalignment resulting from errors in mounting, shaft deflection and distortion of the foundation. It is impossible for this bearing to exert any bending influence on the shaft, a most important

consideration

in

applications

requiring

extreme

accuracy,

at

high

speeds. Self-aligning Ball Bearings are recommended for radial loads and small thrust loads in either direction.

SINGLE ROW, DEEP GROOVE BALL BEARIYGS The Single Row, Deep Groove Ball Bearing will sustain, in addition to radial load, a substantial thrust load in either direction, even at very high speeds. This

advantage

results

from

the

intimate

existing

between

the

balls

and the deep, continuous groove in each ring. When using this type of bearing, careful alignment between the shaft and housing is essential. This bearing is also available with seals and shields, which serve to exclude dirt and retain

lubricant.

ANGULAR

BALL

BEARINGS

The Angular Ball Bearing s a heavy thrust load in one direction, sometimes combined with assuring the highest thrust

a moderate radial capacity and axial

load. A steep angle, rigidity, is obtained by a high

thrust ing shoulder on the inner ring and a similar high shoulder an the opposite side of the outer ring. These bearings can be mounted singly or, when the sides are flush ground, in tandem for constant thrust in one direction; mounted in pairs, also when sides are flush ground, for a combined load, either face-to-face

or

back-to-back.

DOUBLE ROW, DEEP GROOVE BALL BEARINGS The

Double

Row,

Deep

Groove

Ball

Bearing

embodies

the

same

principle

design as the single row bearing. However, the grooves for the two

rows

of of

balls are so positioned that the load lines through the balls have an outwardly converging angle. This bearing has a lower axial displacement than occurs in the single row design . . . substantial

thrust

capacity

in

either direction . . . and high radial capacity due to the two rows of balls.

6

\

SPHERICAL ROLLER BEARINGS

The Spherical Roller Bearing, due to the number, size and shape of the rollers, and the accuracy with which they are guided, has unexcelled capacity. Since the bearing is inherently self-aligning, angular misalignment between the shaft and housing has no detrimental effect and the full capacity is always available for useful work. The design and proportion are such that, in~addition to radial load, heavy thrust load may be carried in either direction.

CYLINDRICAL ROLLER BEARINGS The

Cylindrical Roller Bearing

has

high

radial

capacity

and

provides

accurate

guiding of the rollers, resulting in a close approach to true rolling. Consequent low friction permits operation at high speed. Those types which have flanges on one ring only, allow a limited free axial movement of the shaft in relation to the housing. They are easy to dismount even when both rings are mounted with a tight fit. The double row type assures maximum radial rigidity and is particularly

suitable

for

machine

tool

spindles.

SPHERICAL ROLLER THRUST BEARINGS The

Spherical Roller Thrust Bearing

is designed to carry heavy thrust loads, or

combined loads which are predominantly thrust. This bearing has a single row of rollers which roll on a spherical outer race with full self-alignment. The cage, centered by a cage guide sleeve, is constructed so that lubricant is pumped directly against the inner ring’s unusually high guide flange. This insures good lubrication between the roller ends and the guide flange. The spherical roller thrust

bearing

operates

best

with

relatively

heavy

oil

lubrication.

TAPERED ROLLER BEARINGS Since the axes of its rollers and raceways.form an angle with the shaft axis, the Tapered Roller Bearing is especially suitable for carrying radial and axial loads acting simultaneously. A bearing of this t y p e u s u a l l y m u s t b e adjusted toward another bearing capable of carrying thrust loads in the opposite (inner

direction.

rings)

with

Tapered

rollers

and

Roller their

cups

Bearings (outer

are rings)

separable-their are

mounted

cones

separately.

SHIELDS, SEALS AND SNAP RINGS

Ll OllP3 Shield

Suffix 2

Two Shields

SufFix

22

Two Red Seals

Snap Ring On Outer Ring

Snap Ring On Outer Ring On Opposite Side To One Shield

Snap Ring On Outer Ring On Some Side As One Shield

Suffix RS

Sulfix 2RS

Suffix NR

Suffix ZNR

Suffix ZNBR

ANGULAR IN

FACE-TO-FACE

Snap Ring On Snap Ring On Outer Ring On Outer Ring On Opposite Side Same Side T o O n e R e d S e a l A s O n e R e d Seal Sut%x

RSNR

Suffix RSNBR

BA L L BEARINGS DUPLEX MOUNTINGS

BACK-TO-BACK

PARTS AND ASSEMBLY OF

Tapered Bore Bearing

8

l.l

One Red Seal

TANDEM

SIC F ADAPTER BEARINGS

Adapter Mounting

MOUNTING OF BEARINGS -SHAFTS AND HOUSINGS CLEANLINESS

MOUNTING DESIGNS The

successful

application

of

a

ball

or

roller

bearing

intrusion of dirt and other foreign matter cannot be over emphasized. Seals must be designed to prevent

depends to a great degree on two factors: l the mounting design l

the accuracy of the various machined surfaces upon which the bearing is ed.

Unless care is exercised in both deg the bearing mounting

and

machining

the

various

parts,

The importance of protecting the bearing from the

a

prema-

ture failure may result. This is true, even though the capacity of the bearing specified may be well above the applied load.

the entrance of any type of foreign matter to the bearing. Dirt will act as a perfect lapping compound and will grind the bearing surfaces. This will result in excessive wear of the rolling elements and of the inner and outer rings. In addition, foreign matter will contaminate the lubricant-and gradually break down the oil or greose to the point where effective lubrication cannot be obtained. Dirt will also cause noisy operation.

The narrow width of a ball or roller bearing provides a comparatively small surface area for the applied

The

load. Hence, the unit pressures are high and must be uniformly distributed to the ing surfaces of both

be large enough to provide for an adequate amount of lubricant. Seals should be effective in retaining the

the shaft and the housing. Therefore, it is evident that both the inner and outer rings must be properly

lubricant in the housing.

mounted on the shaft and in the housing respectively. Serious distortion is eliminated and uniform distribu-

cavity

in

the

housing

around

the

bearing

should

MOUNTING AND DISMOUNTING

tion of the Ioad is obtained. Bearings may be mounted directly on the shaft or on This same care must also be used with respect to the

tapered

pedestal on which the bearing housing is mounted. Distortion of the bearing housing will occur, unless the

odapter

sleeves.

When mounted directly on the shaft, the inner ring

pedestal is firm and the surface true.

should

be

height.

Proper

located shaft

against

a

shoulder

shaft heights

shoulder are

of

listed

proper in

the

A bearing housing should be designed to permit a simplified assembly and disassembly of the component

Bearing Catalogs. This shoulder must be machined

parts. Such design should also provide for simple

be used. The radius of the fillet must clear the corner

methods of casting, with few machined surfaces-to reduce costs to a minimum.

radius of the inner ring. This also applies when mounting the outer ring in the housing. Generally

Shaft filler Too Large

square with the bearing seat and a shaft fillet should

Correct

Shaft F i l l e t

9

Shaft Shoulder Diameter Too Large

Shaft Shoulder Diameter Too Small

speaking, bearing applications have a rotating inner ring with a stationary load applied to the bearing. In such cases, it is necessary to mount the inner ring with a press fit on the shaft-and the outer ring with a slip fit in the housing. If the inner ring is loose on the shaft, creeping will occur. This will result in overheating, excessive wear and

erosion

between

the

shaft

ond

the

inner

ring. The explanation of creeping action can be simplified by the use of this comparison. Compore the action of on internal gear in mesh with a planet pinion.

Correct Shaft Shoulder Diameter

speed of the shaft (planet gear) would be greater than the speed of the inner ring (ring gear)-and sliding would toke place. Therefore,

it

is

an

obvious

conclusion

that

a

preventive

measure must be token to eliminate creeping and its harmful results. Mount the inner ring with a sufficient press fit on the shaft! This will insure that both inner ring ond shaft act as a unit-and both rotate at the same speed. It is also desirable to use a locknut to clamp

the

inner

ring

agoinst

the

shaft

shoulder.

If the opplied load is of a rototing nature, for example

If the planet pinion (representing the shaft), hod one tooth less than the internal gear (representing the

-vibrating screens where unbalanced weights are attached to the shaft, then the outer ring becomes the

bearing inner ring), the latter would slip back one geor

critical member. In order to eliminate creeping in this case, the outer ring must be mounted with a press fit

tooth

in

each

full

revolution

of

the

shaft.

Hence,

the

V-Belt ond Sprocket Drive, Resulting in Stationary Loads and Rotating Inner Rings

10

in the housing. The rotating inner ring, when subjected to a rotating load, can be mounted with a slip fit on the shaft It is evident, therefore, thot when the applied load is stationary with respect to the outer ring, a tight shaft fit is required When the applied load is stationary with respect to the inner ring, a tight housing fit is required Small bearings may be pressed on the shaft by using a piece of tubing. Pressure is applied to the inner ring of the bearing by the tubing. The assembly of larger open bearings can be simplified by a “heating” procedure Boil the bearing in an emulsion of 10% to 15% soluble oil in water. Make sure the bearing is placed on a grating so it does not touch the sides or bottom of the container Temperature control is automatic but sufficient time should be allowed to assure that the bearing is heated throughout This will sufficiently expand the bearing and permit it to slide easily over the shaft to its proper location Care should be taken to prevent cocking of the inner ring as this may cause it to seize before the bearing is properly located If this happens, it is best to remove the bearing promptly and reheat When the bearing coots, it will shrink and grip the shaft It requires only a little ingenuity to provide the tools to facilitate this procedure An electric hot plate or an induction heater can also be used to heat an open beoring. Temperature should not exceed 121 °“C (250°F) Assembly of sealed bearings can be accomplished by heating the bearing to a maximum of 107°C (225°F) with either a hot plate or an induction heater and proceed as mentioned above for mounting the bearing.

SHAFT AND HOUSING FITS A ball or roller bearing has extremely accurate component parts which fit together with very close clearances. The inner ring bore and the outer ring outside diameter must be manufactured within close limiis to fit their respective ing -the shaft and the housing It follows that the shaft and housing must also be machined to close limits Only then, will we obtain the required fits when the bearing is mounted. It is advisable to refer to the tables of shaft and housing fits as published in the SKF Engineering Data Catalog. These tables list recommended dimensions and tolerances for various types of shaft and housing fits suitable for various operating conditions.

ADAPTER SLEEVE The use of a topered adapter sleeve on standard shafting will greatly simplify the mounting of the bearing. The outer surface of the sleeve is tapered to match the tapered bore of the beoring inner ring. This will provide the required tight fit between the inner ring and the shaft The adapter sleeve is slotted to permit easy contraction and is threaded at the small end to fit a locknut When the locknut is tightened to the recommended Reduction in Internal Radial Looseness, the correct interference between inner ring and shaft is achieved.

A lockwasher between the inner ring and the locknut prevents the nut from loosening. The use of micronized graphite will greatly facilitate assembly -and help prevent erosion of the parts A light coating of graphite is applied on the 0.D adapter sleeve. It is good practice to apply a coat. of oil to the housing and component parts before the bearing unit is assembled.

INTERNAL BEARING FITS It is evident that a press fit between the parts will stretch the inner ring. This holds true when mounting the bearing directly on the shaft or by means of an adapter sleeve. Thus, there will be a tendency to reduce the initial internal radial clearance in the bearing. If an excessive press fit is used, it is possible to reduce the bearing clearance sufficiently to make the bearing tight. However, if the recommended shaft fits are used and operating temperatures have been taken into , the internal clearance remaining after mounting the bearing will be sufficient to insure proper operation. When an adapter mounting is used, some additional cautions should be heeded If these are taken into consideration, the bearing will not be tight internally. The following is the recommended practice for mounting selfaligning ball bearings on adapters. Mount bearing on adapter sleeve, starting with the large bore of the inner ring to match the taper of the adapter. With the bearing hand tight on the adapter, locate bearing to the proper axial position on the shaft [Do not apply lockwasher at this time because drive up procedure may damage lockwasher.) Apply the locknut with chamfered face toward the bearing after lubricating the face of the locknut next to the bearing. Hand tighten the nut with a spanner wrench until the adapter sleeve can neither be moved axially nor rotated on the shaft. Then with a hammer drive the spanner wrench until the locknut has been turned 90’ or ¼ turn on the adapter sleeve. CAUTION: A loose adapter sleeve can lead to the inner ring turning on the adapter sleeve and/or the adapter sleeve turning on the shaft. To insure that the nut is not excessively tight, make certain the outer ring of the bearing rotates freely. When mounting a normal fit bearing, swiveling the outer ring will result in a slight drag If the bearing is a C3 fit, the outer ring will swivel freely. Before mounting spherical roller bearings on adopters, the internal cleoronce should be checked and recorded Measure the unmounted internal clearance in the bearing by inserting progressively larger feeler blades the full length of the roller between the most vertical unloaded roller and the outer ring sphere Do not roll the feeler blade through the clearance; slide it through Record the measurement of the largest size blade that will slide through. This is the unmounted internal clearance. The bearing should be resting upright on a table when making this check

11

reduces

the

internal

clearance

in

the

bearing-in

addi-

tion to the reduction due to the tight fit on the shaft. To

compensate

for

this

additional

reduction

of

internal

clearance in the bearing, some provision must be made. Bearings

Adapter Mounting

After

mounting

sleeve,

the

the

locknut

bearing is

on

tightened

the

to

shaft

and

suficiently

adapter

to

reduce

the initial clearance by the required amount. This is checked in the same manner as above, by using the feeler

gauge.

The

mounting can be Catalog 140-l 10.

decrease found

in in

internal SKF

with

an

internol

clearance

grearer

than

standard should be used. This additional clearance will compensate for internal clearance reduction due

clearance

Engineering

after Data

the

temperoture

differential

between

the

outer rings. There are other cases where internal clearance greater than standard

inner

and

bearings with are required.

Among these are dryer cylinder bearings in paper machinery where steam es through the hollow shaft - shaker screens where tight housing required

-

high

speed

applications

where

fits are the

tem-

perature rise in the bearing, due to speed and load, is abnormal - etc. It is desirable that such cases, and applications where extremely

high

temperatures

are

involved,

be

referred

TEMPERATURE CONDITIONS

to the SKF Applications Engineering Department.

Certain types of bearing applications require the consideration of variable temperature conditions.

If this additional internal clearance is not provided,

For Example: An induced draft fan handling gases at high temperature. The fan wheel is mounted on the

temperotures

shaft. Therefore, thatport

the bearing will be excessively tight internally and cannot operate successfully. Excessive high operating lubricant

due

and to

subsequent

carbonization

break-down

will

of

the

occur.

of the shaft in the fan casing

is subjected to the high temperatures. The bearings are usually mounted directly outside the fon casing. Thus, the temperature of the shaft at the bearing location is

FREE AND HELD BEARINGS

considerably higher than the room temperature. It follows that the inner ring of the bearing (mounted on

A temperoture variation will expand or contract the

the shaft) will be considerably hotter than the outer ring. This is true, as the outer ring is mounted in the housing which is isolated from the fan and not subjetted to the high temperoture. As a result, the inner ring will expand more than the outer ring. This action CLEARANCES TO PERMIT AXIAL MOTION

Free

12

Bearing

component parts of any machine. Due to this condition, it is essential that such parts be permitted to expond or contract without restriction. For that reason, only one bearing on any one shaft should be fixed axially in the housing (called a “held” bearing) to prevent axial or end motion. STABILIZING RING TO LOCATE BEARING AXIALLY MOUNT IT ON LOCKNUT SIDE

Held Bearing

All other beorings on that same shaft should have adequate as “free” shaft

to

axial clearance in the housing (referred to bearings). Such free bearings will permit the elongate

and

contract

without

restriction.

In gear reducers where herringbone gears are used, only one bearing on one of the shafts should be “held,” usually the input shaft. It is evident that the “V”

shape

adding lubricant to the bearing. After the lubricant is added, remove the plug (preferably at the lower holf of

the

housing)

while

the

bearing

is

in

operation.

This

permits the excessive lubricant to flow out of the housing and relieve the internal pressure. When the flow of grease ceases, be sure to replace the plug. Speed

and

other

operating

conditions,

in

some

cases,

of the gear teeth will locate the other shaft axially.

require that oil lubrication be used. In that event, the bearing housing should be equipped with adequate

When a flexible coupling is used to connect two shafts,

oil fittings. Such fittings should provide a static oil level at the center of the lowest ball or roller in the bearing.

a “held” bearing is required on each of the shaftsas a flexible coupling permits end motion of both shafts.

It is preferable to use sight glass oil gauges which can be clearly marked for static and operating levels. The operating level is slightly lower than the static

LUBRICATION

level due to agitation of the oil.

The bearing unit can usually be lubricated with a good grade of lithium base grease for normal loads, speeds

The static level can be marked on the gauge before

and

determined

be

operating filled

conditions.

approximately

The

bearing

one-third

full

housing with

should

grease.

the unit is assembled. The operating level can be

An excessive quantity of grease will “build up” in-

drop

ternal pressure in the bearing housing and result in

to

high temperatures-and subsequent damage to the bearing. Here is a safety

measure to combat this danger when

only

after

the

bearing

is

in

operation.

The

gauge should also be marked for the operating level and the lubricant, at no time, should be permitted to below

the

static

this

point.

marks

But, never restore the oil level

while

the

bearing

is

running.

The subject of lubrication is discussed in greater detail in another publication, A GUIDE TO BETTER BEARING LUBRICATION,

144-l

10.

13

DO’S AND DON’TS FOR BEARINGS .s. assembly, maintenance, inspection and lubrication Do work as close to the ideal conditions pictured here. Dividends in bearing performance will result.

Don’t work under the handicap of poor tools, rough

DO

work

DON’T work in dirty surroundings.

DO

remove

with

exposing

clean all

tools,

outside

in

clean

dirt

surroundings.

from

housing

before

bearings.

bench,

plenty

of

dirt.

DON’T use wooden bench tops.

mallets

or

DO handle with clean, dry hands. -

DON’T

use

DO treat a used bearing as carefully as a new one.

DON’T

handle

DO use clean solvents and flushing oils.

DON’T

spin

DO lay bearings out on clean paper.

DON’T

spin

DON’T rinsing

use same container of bearings.

DON’T

use

DO protect moisture. DO

DO

use

disassembled

clean,

keep

lint-free

bearings

rags

wrapped

bearings

if

from

bearings

in

are

oil-proof

dirt

and

wiped.

paper

when

not in use.

clean

inside

DO

install

new

DO

of

housing

bearings

as

before

replacing

removed

bearings

uncleaned

any

or

chipped

with

or

keep

dirty

tools.

moist

hands.

bearings.

bearings

cotton

dirty,

rough

with

waste

compressed

for

or

air.

cleaning

dirty

cloths

and

final

to

wipe

bearings.

from

bearings. packages,

time.

DON’T

scratch

or

nick

DON’T

remove

grease

DON’T

use

bearing

surfaces.

washing.

bearing

lubricants

clean

cover containers when not in use.

14

brittle

on

DON’T expose bearings to moisture or dirt at any

DO

without

dirty,

work

when

applying

or

oil

from

new

kind

or

amount

bearings.

and incorrect

of

lubricant.

To press becring oh shaft, Fit c,

Proper core begins in the stock room. Store bearings in

clean piece of tubing aver the shaft and rest it an inner ring Befare p r e s s u r e i s a p p l i e d t c b e a r i n g , a p p l y a c o a t o f Iighl oil or micronized graphite to the b e a r i n g s e a t a n d t h e bearing bare This will facilitate assembly Be sure bearing is square an shaft, then apply pressure by tapping end of pipe with hommer or using arbor press. Refer to illustration (A) an page 16

originol unopened packages, in o dry place. The bearing number isplainly shown on the wrapping. Before packaging, the manufacturer protected the bearing with a grease coating. An unopened pockage means continued protection. Do not open carton until reody to use.

Open package only when ready to install bearing. Hondie bearing with clean, dry hands and with clean rags. Lay bearing on clean paper and keep covered. Never expose bearing on a dirty bench or floor. Never use o beoring as o gauge lo check either the housing bore or the shaft

fir. Note: To shrink a sealed bearing an a shaft, use only method 2, and limit temperature to 107°C (225°F).

Don’t wash o new bearingit is already clean and the slushing oil should not be removed. Old grease can be washed from a used bearing with a solvent but fluid and container must be clean. After this cleaning, wash the bearing out thoroughly with light oil and then relubricate. Bearings should be washed only when necessary.

Before mounting, be sure shaft size is within the specified tolerances recommended for the bearing. The bearing seat should be perfectly round and not tapered. It should be clean and free from nicks ond burrs. Shaft shown is too worn lo properly seat bearing-don’t use it. shaft firmly in a clean place-if in a vise, protect it from vise jaws. Protectors can be soft metal, wood, cardboard or paper.

To shrink an open bearing an a shaft, expand bearing by: 1. Boiling in emulsion of 10% to 15% soluble oil in water for 15 to 30 minutes .Be sure to place s under bearing to isolate it from bott container as will overheat bearing 2 Heat in a clean temperature-con. trolled electric oven or on a hot plate to a maximum of 121°C 125O°F) for about fifteen minutes Thoroughly bearing but do not overheat This will prevent seizing on the cold shaft Alter bearlng is in place against shaft shoul. der. lock it immediatelv with a lock nut Otherwise, in shrinking, bearing may move away from its proper posi. tion against shaft shoulder

When mounting in a split housing, check bore of housing to see that it is within specified perfectly

tolerances round.

and

Bearing

is

must

not be pinched by small bore or because of a cocked outer

ring. Don’t switch housing caps - t h e y a r e n o t interchangeable. An undersized housing bore or on out-of-round bore will pinch the bearing cause early failure.

and

Some precaution must be exercised when mounting bearing in a solid housing; i.e., the outer ring should be perfectly square with the housing bore before any pressure is applied. Here again, the housing bore should be within the specified tolerances for the bearing size and should be perfectly round. The housing bore and bearing outside diameter should be coated with l i g h t o i l o r m i c r o n i z e d graphite to facilitate assembly.

15

(A) An arbor press is equally good for either mounting or removing beorings.

Cover the unfinished job when left for only a few hours or until the next day. Rewrap each bearing to keep out dirt and moisture. When this & necessary, use grease-proof paper. lf you do not take care of bearings during installation, they will not lost long.

Type of lubricant usually depends on operating conditions -follow machine builder’s instructions. When oil is used, cover about half of bottom ball or roller. It is preferred that o sight oil gauge be used and marked so as to show static and operating oil levels. This will greatly help to determine when additional oil is required. The operating level is different than the static level and can be determined only when the bearing is in operation. Bearing pullers which may be used separately or in various combinations to pull or push complete beorings or individual rings.

Be sure bearing is square with and held fhmly against shaft shoulder. Secure it with a locknut and lockwasher. Housing covers must be tight to keep lubricant in and dirt wt. After heid beoring has

(Cl

been positioned, the free bearing should be located centrally in its housing to p e r m i t expansion a n d traction of the shaft.

Never pound directly on o bearing or ring. It will likely damage both

can-

shoft and bearing.

To remove o bearing from the shaft, force inner ring with press or draw bar and plate. Shaft shoulder must be smaller than inner ring to make such removal. A variety of beoring pullers are ovailable. The use of such speciaiized tools will more than pay for themselves by preventing damage to serviceable bearings. Refer to group at right.

16

of

illustrations

(8)

To drive shoft ‘2 of beoring, use a soft metal slug which will not mar the shaft.

INSPECTION and ASSEMBLY REQUIRE CLEAN BEARINGS

\

Don’t try to judge the condition of a beoring until after it has been cleaned. Don’t spin dirty bearings. Rotate them slowly washing.

while

Don’t spin ony bearings with an air hose. Rotote one ring by hond when using air to expose all parts of bearing. Bearings with a shield or seal on one side only should be washed, inspected ond handled in the same manner as bearings without shields or seals. Do not spin bearings before cleaning Dirt can cause serious scratching.

Bearings with shields or seals on both sides should not be woshed. Wipe them off to keep dirt from working inside. Smooth turning bearings can be coated with protective lubricant, then wrapped in their original application.

and

stored

or

used

If a small tank and wire baskets for soaking and washing

bearings

are

not

available,

a

clean

grease

can or bucket filled with solvent can be used. Let the bearings soak long enough to loosen the grease and i

dirt. Thot may toke several hours or longer. Then slosh the bearing around near the top of the container, giving it a turn now and then until it is clean. Rinse in a clean Bearing

container of clean cleaning

solutions

solvent. are

generally

petroleum

sol-

vents intended for bearing cleaning and are preferred. Soak bearings thoroughly in plenty of solvent

Rinse them in clean solvent, light oil or kerosene.

Do not

spin

by force of air. Hold both rings. Use clean, dry air.

17

All solvents are highly inflammable and precautions

other

should be taken to prevent fires.

as long

A

short,

clean

bristle

not come out or scale or chips.

After

the

inspect

Inspected to

use

from

off

is

which

helpful

the in

bristles

will

removing

dirt,

hove

been

thoroughly

cleaned,

immediately.

bearings

again,

which

but

can’t

are be

considered reossembled

good in

enough

the

equip-

ment on the same doy, should be dipped in slushing c o m p o u n d arid stored overnight in a tightly covered

If inspected bearings are to be stored for more than a few days, dip them in a protective lubricant or coat surfaces

with

matter.

Any

clean

cloth or paper

will

do

the bearings are well covered.

oil is specified. Be sure to use exactly the kind of lubricant Store

a

light

grease,

rototing

them

to

work

the grease thoroughly around the rolling and on the raceways. Wrap the beorings in greaseproof

the

grease

instructions in

clean

specify. containers.

Handle

grease

with

clean paddles or grease guns. Keep grease containers covered.

overfill.

Grease

or

oil

will

purge

out

of

overfilled

housings past seals and closures, collect dirt and cause trouble. Too much lubricant will also cause overheating. This is particularly true of bearings running speeds where the churning of the lubricant the bearings to run excessively hot.

at high will

cause

paper and place in o clean box or carton. Where

Don’t permit any machine to stand around for months

cartons ore not obtoinoble, wrap them in o waterproof paper and mark the outside of the pockage to identify

without turning it over once in a while so that all

the bearing.

Oil tends to drain down off a standing bearing and -

not

DO

Cover

leave

the

bearings

bearings

exposed

until

in

ready

portial to

assemblies.

complete

18

porfiolly

ossembld will collect harmful dust or dirt if left standing too long.

corrosion.

the

assembly, to p r e v e n t d a m a g e b y m o i s t u r e , d i r t o r

Bearings

surfaces of the bearings will be covered with lubricant. moisture may condense in the housing and cause

-

Inspect

seals

and

vents

, I

DO’S ad DON’TS on LUBRICATION

Don’t

pan.

all

OS

Follow instructions when furnished with machinery. Use only grease where grease is specified and oil where

bearings

them

brush

break

foreign

regularly.

if assembly will not Cover with c/eon cloth or-paper, especially be completed for several hours or until next doy

TROUBLESHOOTING This section presents some helpful hints on bearing troubleshooting-what complains,

how

to

recognize

the

reason

for

the

trouble

and

practical

t o look for when a customer

solutions,

wherever

possible.

Complaints of bearing trouble can be reduced to a few classifications-listed in the following order. For ease of relating them to conditions and solutions, they are coded A to G inclusive.

A

-

Overheated

bearing

B-- Noisy bearing

CUSTOMER’S

C

COMPLAINT

D - Vibration

- Replacements are too frequent

E

-

Unsatisfactory

performance

of

equipment

F - Bearing is loose on shaft G - Hard

The

following

table

lists

some

turning

typical

shaft

conditions

that

will

result

in

bearing

failures.

The f i r s t c o l u m n n u m e r i c a l l y c o d e s e a c h t y p i c a l c o n d i t i o n ( N o s . 1 t o 5 4 i n c l u s i v e ) . The

third column is the customer-complaint code (A to G) to which the condition

may apply.

TYPICAL CONDlTlONS RESULTING IN BEARING FAILURES EACH CONDITION COULD CAUSE -ANY ONE OF THE COMPLAINTS LISTED OPPOSITE THE RESPECTIVE CONDITION IN COLUMN 3 CODE

CONDITION

COMPLAINT

1.

lnadequote lubrication (Wrong type of grease or oil). . . . . . . . . . . . . . . . . . . . . . . . . . .

2.

Insufficient

3.

Excessive lubrication (Housing oil level too high or housing packed with grease). . . . . . . .

4.

Insufficient

lubrication

oil level - l o s s of

(Low

clearance

in

bearing

5.

Foreign

matter

acting

as

on

6.

Foreign

matter

acting

as

a

7.

Bearings

pinched

8.

Bearings

pinched

in

9.

Uneven

shimming

of

10.

Chips

in

11.

High

air

12.

Seals

too

in

the

bearing

housing

velocity

over

tight

(Cup

carbon,

corrosive

(Water,

acids,

base

(Chips

bearings

through

seals). . . . . . . . . . . . . .

A-B-C-G I-

fit). . . . . . . . . . . . . . . . . . . . . . . . .

wrong

(Sand,

housing

housing

of

abrasive

housing

the

(Selection

lubricant

etc.). . . . . . . . . . . . . . . . . . . . . . . . paints,

A-5-C-G

etc.). . . . . . . . . . . . . . . . . .

A-G A-B-C-E-G B-C-D-E-G B-C-D-E-G

round). . . . . . . . . . . . . . . . . . . . . . . . . . . .

A-B-C-D-E-G

(Housing

warped). . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A-B-C-D-E-G

(Distorted

housing

A-B-C-D-E-G

(Bore

or (Oil

out

dirt

of

left

in

bore

-

possible

cracking

of

base).

.

housing]. . . . . . . . . . . . . . . . . . . . . . . . . .

leakage). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

seals). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

B-C-D-E-G C A-G

19

TYPICAL CONDITIONS RESULTING IN BEARING FAILURES (Continued) CODE

COMPLAINT

CONDlTlON

13. 14.

Seals

Oil return holes plugged (Oil leakage). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A

15.

Preloaded

A-B-C-G

16. 17. 18. 19. 20. 21. 22 . 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54.

20

misaligned

(Rubbing

bearings

against

(Opposed

stationary

parts). . . . . . . . . . . . . . . . . . . . . . . . . . . .

mounting). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Preloaded bearings (Two held bearings on one shaft). . . . . . . . . . . . . . . . . . . . . . . . Bearing loose on shaft (Shaft diameter too small). . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bearing loose on shaft (Adapter not tightened sufficiently). . . . . . . . . . . . . . . . . . . . . . . Bearing

too

tight

internally

(Adapter

tightened

excessively), . . . . . . . . . . . . . . . . . . . . .

A-B-G

A-B-C-E-G B-C-D-E-F B-C-D-E-F A-E-C-E-G

Split pillow block with uneven surfaces (Oil leakage). . . . . . . . . . . . . . . . . . . . . . . . . . .

C

Spinning of outer ring in housing (Unbalanced load). . . . . . . . . . . . . . . . . . . . . . . . . . .

A-C-D-E

Noisy bearing (Flat on roller or ball due to skidding). . . . . . . . . . . . . . . . . . . . . . . . . . .

B-D-E

Excessive shaft expansion (Resulting in opposed mounting). . . . . . . . . . . . . . . . . . . . . . .

A-B-C-E-G

Excessive shaft expansion (Resulting in insufficient clearance in bearing). . . . . . . . . . . . .

A-C-E-G

Tapered shaft seat (Concentration of load in bearing). . . . . . . . . . . . . . . . . . . . . . . . . .

C-D-E

Tapered housing bore (Concentration of load in bearing). . . . . . . . . . . . . . . . . . . . . . .

C-D-E

Shaft

shoulder

too

small

(Inadequate

shoulder

-bending

of

shaft) . . . . . . . . . . .

C-D-E-G

Shaft shoulder too large (Rubbing against bearing seals). . . . . . . . . . . . . . . . . . . . . . . .

A-B-C

Housing

shoulder

too

small

(Inadequate

C-D-E-G

Housing

shoulder

too

large

(Distortion

shoulder

). . . . . . . . . . . . . . . . . . . . . . .

bearing

seals). . . . . . . . . . . . . . . . . . . . . . . .

of

Shaft fillet too large (Bending of shaft) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Housing

). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C-D-E-G

clearance in labyrinth seals (Rubbing). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A-B-C-G

fillet

Insufficient

B-C-G C-D-E-G

too

large

(Inadequate

Oil gauge breather hole clogged

(Shows incorrect oil level). . . . . . . . . . . . . . . . . . . . . .

A-C

Shafts out of line (Linear misalignment). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A-C-D-E-G

Shafts out

A-C-D-E-G

of

line

(Angular

misalignment). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Constant oil level cups (Incorrect level). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A-C

Constant oil level cups (Located against rotation of bearing]. . . . . . . . . . . . . . . . . . . .

A-C

Lockwasher

prongs

bent

(Rubbing

Incorrect positioning of fingers

against

bearing). . . . . . . . . . . . . . . . . . . . . . . . . . .

(Rubbing against covers). . . . . . . . . . . . . . . . . . . . . . . . . .

A-B-E-G A-B-C-G

Pedestal surface uneven (Bending of housing causing pinching of bearing). . . . . . . . . . .

A-C-D-E-G

Ball or roller denting (Hammer blows on bearing). . . . . . . . . . . . . . . . . . . . . . . .

B-C-D-E

Noisy

B

bearing

(Extraneous

conditions). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Lubricant leakage and entrance of dirt into bearing (Worn out seals). . . . . . . . . . . . . Vibration

(Excessive

Vibration

clearance

(Unbalanced

in

bearing). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

loading). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C D-E D-E

Hard turning shaft (Shaft and housing shoulders out of square with bearing seat). . . . . . .

C-E-G

Bearing loose on shaft (Knurling

A-F

and center punching of shaft for bearing seat).

. . . . . .

Discoloration of bearings (Use of blow torch to remove bearing). . . . . . . . . . . . . . . . . .

a

Oversized

A-B-C-E-G

shaft

Undersized Oversized Enlarged Noisy

(Overheating and noise). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

housing housing

housing

bearing

bore bore

bore

(False

(Overheating (Overheating

(Excessive

of of

peening

bearing). . . . . . . . . . . . . . . . . . . . . . . . . . . .

A-B-C-E-G

ring). . . . . . . . . .

A-B-C-D-E

housings). . . . . . . . . . . . . . .

A-B-C-D-E

bearing-spinning of

non-ferrous

of

outer

brinelling). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

B

The

following

customer’s

pages

offer

PRACTICAL

SOLUTIONS

to

the

TROUBLE

CONDITIONS

which

originated

~

.your

complaint.

Column

1 refers

back

to

Column

2 is the

reason

the for

code that

of

the

condition

typical -ond

condition column

TROUBLE CONDITIONS OVERHEATED Complaint REAS6N

3 is your

grease

in the

foregoing

pracficol

table.

solution.

AND THEIR SOLUTION BEARING “A”

FOR CONDITION

Wrong type of grease ing break-down of

Insufficient

listed

PRACTICAL

SOLUTION

or oil causlubricant.

in housing.

Purge bearing until only lower half of housing is rh to sh full of grease. Using oil lubrication, reduce level to

quate internal clearance ditions where external thru shaft, conducted ng excessively

Housing

bore

Leather or with excessive

Rotatinq

seals

out

for conheat is thereby the in-

of

round.

composition seals spring tension or

rubbing

against

Replacement bearing should have bearing for proper internal clearance. markings have become indistinct.

identical Check

marking as with SKF if

original bearing

Check and scrape housing bore to relieve pinching of bearing. Be sure pedestal surface is Rat, and shims cover entire area of pillow

Replace leather or composition seals with ones having reduced spring tension. Lubricate seals.

Check running clearance ing seal to eliminate Correct alignment.

of rotatrubbing.

21

OVERHEATED

BEARING

-

Complaint

Clean holes. Drain refilling to proper fresh lubricant.

Opposed

insert cover loading

mounting.

Back ings, quate permit

gasket flange of

“A”

out oil

(Continued)

used level

oilwith

between housing to relieve axial bearing.

and pre-

off covers in one of the housusing shims to obtain adeclearance of outer ring, to free axial bearing motion.

Loosen locknut and sleeve assembly. Retighten sufftciently to clamp sleeve on shaft but be sure bearing turns freely.

ing

incorrect bricant

oil in

level. bearing.

Result:

no

lu-

Clean

with

one

out

having

clogged

proper

hole

to vent

bore.

oil

LINEAR

ANGULAR

MISALIGNMENT

MISALIGNMENT

OVERHEATED DE TO PICA1 IDITION

‘-38

BEARING

-

Complaint

“A”

(Conrinuad)

PRACTICAL SOLUTION

REASON FOR CONDITION

incorrect mounting of constant oil level cup. (Too high or too low.) Cup located opposite rotation of bearing permitting excessive flow of oil, resulting in too high oil level.

The oil level at standstill must not exceed the center of the lowermost ball or roller. Locate cup with rotation of bearing. Sketch illustrates correct position of constant level oil cup with respect to rotation. Better replace constant level oiler

i I IIATIC 01~ L*YGL * WC1).TWC OIL L‘VCL , wawnG .

Prong

39

rubbing

against

Remove prong

bearing.

lockwasher or replace

with

straighten new wosher.

r’

m\

-’

-7

($L

1

”

d

-L-!-iKnurling bearing

48

and seat

center punching on shaft.

of

Unsafisfactory because high spots are flattened when fit is loose, metallire shaft and regrind

50

Bearing seat diameter machined oversize, causing excessive expansion of bearing inner ring, thus reducing clearance in bearing.

Grind

53

“Pounding-out” due to soft larged bore ningyf outer

Rebore bushing

of housing bore metal. Result: en. . . causing spinring in housing.

shaft

to get

proper

fit between

housing and press to correct size.

NOISY

steel

inner

ring

bushing

in

Wrong causing cant.

type of grease or oil break-down of lubri-

Consult reliable lubricant manufacturer for Check SKF Catastructions to determine be used.

2

Low oil through

level. seal.

Oil level standstill.

Insufficient

grease

lubricant

in housing.

Using

should I

grease,

be lower

at

center half

See Illzrsfration-CornpIriillt

4

5

6

7-8

9-51

Bearings selected with inadequate internal clearance for conditions where external heat is conducted through shaft, thereby expanding excessively the inner ring.

Replacement bearing ing for proper internal become indistinct.

Foreign bon, housing.

Cleon design

matter (dirt, etc.) entering

sand, carbearing

Corrosive agents (water, paints, etc.) entering the ing housing. Housing Housing tortion housing

acids, bear-

bore out of round. warped. Excessive disof housing. Undersized bore.

Addition

of

bearing

bore.

and

Machine

shaft.

bore

of

“B”

i

of

when load is applied, to proper size.

BEARING

Complaint

Loss

1 --Y

out bearing to obtain

of

Check and sure pedestal block base.

of

lowest

pillow

“A”,

and

block

identical Check

Replace protection

(or)

bail

Condition

should have clearance.

housing. adequate

a shroud

of

finger

proper type of lubricant. if oil or grease should

or

roller

should

be

“A”.

marking with SKF

worn-out seals of bearing.

to throw

Coudibons

‘/2

to

$+

at full.

.?

off

as original if markings

or

foreign

scrape housing bore to relieve pinching surface is flat, ond shims cover entire

See Iflllstratiofi-Conlplrrillt

in bearing,

7-8-g-41-51

improve

bearhave

seal

matter.

of beoring. Be area of pillow

NOISY DDE TO YPICAL NDITION

10

REASON

Rotating stationary

15

Opposed

-

Complainr

“8”

(Continued)

FOR CONDITION

PRACTICAL

Failure to remove chips, dirt, etc. from bearing housing before assembling bearing unit.

13 3-40

BEAIWG

seals rubbing parts.

against

Carefully

clean

Check Correct

running alignment

See Iliustrdtion Insert gasket pre-loading

mounting.

housing,

and

clearance

of

between bearing.

“held” Excessive

Two shaft.

Shaft

bearings shaft

diameter

on one expansion.

too

small.

Back quote

off covers clearance

and

and

“A”,

cover

housings to permit

not

tightened

sufi-

Retighten on shaft.

adapter

to

get

using free

Adapter

tightened

Loosen sleeve

excessively.

locknut on shaft

and but

I

22

Flat on skidding.

28

Rbbbing against

ball or roller (Result of fast of bearing

shaft seals.

due to starting.1

Carefully surface.

shoulder

Remachine

examine Replace

bails bearing.

shaft

shoulder

or

-

Condition

rollers,

:

,’

r’ ;

--

A

Retighten turns freely.

sufficiently

to

-

clamp

19

looking

to clear

See Ilhtration-Complaint

.\ \. LOOSE

grip

‘rA”,

axial

to obtain adebearing motion.

,\~\‘, ,.

sleeve assembly. be sure bearing

See Illz~stratjon-Compl~jnt

relieve

~

I 19

to

shims axial G-23-24

ob-

firm

rubbing.

1 i

7-18 Adapter ciently.

eliminate

flange

Conditions

to

to

13-33-40

Condition

“A”,

regrind

seal

Condition

in one of the of outer ring

shaft fit

lubricant.

rotating

housing

See Illz,stratjon-CornplJj,II

Metallize rain proper

fresh

“A”,

See Illustration-Complaint

6-23

use

of

-Complaint ’

SOLUTION

for

flat

spots

on

the

seal.

“A”,

Condition

28 --

30

Distortion

39

Prong

of

bearing

rubbing

against

seals.

Remachine clear seal.

bearing.

Remove

housing

shoulder

lockwasher-straighten


42

incorrect Hammer

method of mounting. blows on bearing.

Replace with when mounting.

43

Interference parts of

of machine.

Carefully provide

Distorted 49

24

of

bearing

shaft

other

and

assembly.

movable

other

parts

to

check necessary

new

prong

“A”, bearing.

every moving clearance.

or replace

Condition Don’t

part

hammer

for

with

new

washer.

of

bearing

39 any

interference.

part

Reset

Only in extreme cases should a torch be used to faCihte of a failed bearing. Care should be exercised to avoid concentration at any one point so distortion is eliminated.

parts

removal high heat

to

NOISY ’

ODE TO ‘YPICAL lNDlTlON

50

-

Complaint

“5”

(Continued)


PRACTICAL SOLUIION

Bearing sear diameter machined oversize causing excessive expansian of bearing inner ring, thus reducing clearance in bearing.

Unbalanced

54

BEARING

load.

Housing

bore

Grind and

shaft shaft.

to

Rebalance

unit.

get

proper

Replace

housing

one

ring

of

having

proper

bearing

bore.

Bearing while

Carefully equal to

exposed machine is

wrong

type

1

causing

break-down

2

Low oil through

level. seal.

Insufficient

to idle.

vibration

examine the spacing

ARE

of

grease

or

oil

bearing for wear spots of the balls. Replace

TOO

by

distance

“c”

of lubricant.

Consult reliable lubricant manufacturer for Check SKF Catastructions to determine be used.


of

Oil

or roller

Loss grease

in

lubricant housing.

level

Using

Bearings selected with quate internal clearance ditions where external conducted thru shaf+,

inadefor conheat is thereby

expanding ner ring.

the

should

grease,

be

at center

lower

half

excessively

in-

Foreign matter (dirt, sand, carbon, etc.) entering into bearing housing.

Clean seal

6

Corrosive agents (water, paints, etc.) entering the ing housing.

Addition

acids, beor-


Failure to remove chips, etc. from bearing housing fore assembling bearing

dirt, be. unit.

of of

lowest

pillow

“A”,

out design

bearing housing. to obtain adequate

of

a shroud

Check and scrape Be sure pedestal pillow block base.

and

housing surface

See Ihtration-Complaiaint

Carefully

clean

housing,

Ior)

is

block

should

flinger

bore flat,

be

identical Check

to throw

fresh

‘/2

to


seals bearing.

ofF the

to relieve and shims

Conditions

use

in bearing. $$ full.

2

Replace worn-out protection of

“A”,

and

ball

Condition


5

Housing Housing tortion housing

separated bearing.

FREQUENT

See Illzi~t~ation-Complaint

10

with

inner

Rebore housing and press steel bushing in bore. Machine bore of bushing to correct size. If loads are not excessive, tighter fit in housing, without the use of the steel bushing, may correct the trouble.

Complaint

7-8-9 11-51

between

“Pounding-out” of housing bore due to soft metal. Result: enlarged bore . . . causing spinning of outer ring in housing.

REPLACEMENTS

4

fit

or

foreign

pinching of cover entire

original bearing

improve

matter.

bearing. area of

7-8-9-4 I-5 I

lubricant.

25

REPLACEMENTS CODE 10 TYPICAL ONDITION

REASON

ARE

TOO

FREQUENT

-

C~mploint

“C”

FOR CONDITION

PRACTICAL

11

Oil leakage resulting from air flow over bearings. (Example: forced draft fan with air inlet over bearings.)

Provide

15

Opposed

Insert gasket pre-loading

mounting.

proper

of

Two

16

17

“held”

shaft.

,*

s

bearings

Excessive

Shaft Adapter

on

shaft

one

expansion.

diameter

too

insufficiently

Back quote

to. divert

direction

between bearing.

housing

and

covers clearance

“A”,

small.

Metallize

shaft

Retighten

adapter

and

regrind


19

Adapter

tightened

Loosen sleeve

excessively.

locknut on shaft

grip

“B”,

and but


using free

“A”,

relieve

axial

shims axial


16-23-24

fit.

shaft.

Conditions


to

IS

proper on

flow.

flange

Conditions

to obtain firm

air

cover

housings, to permit

“A”,

to get

of

Condition

in one of the of outer ring,

off


tightened.

SOLUTION

baffles


23-24

(Continued)

I 7- I 8


Condition

sufficiently

to clamp

19 “UCVLHMFACES

Oil leakage at housing Jxcessive loss of lubricant.

20

split.

If not gasket Replace

severe, cement. housing

--l

use thin layer of Don’t use shims. if necessary.

OR I P’s

@

.OR i; ‘P

/

L!I!QL 21-52

25

s

Unbalanced too large.

26

Unequal bearing.

lood.

l-lousing

bore

Rebalance

machine.

Replace

housing


load

distribution

27

Inadequate causing

bending

shoulder of

29

Inadequate causing

cocking of

28

Rubbing against

of bearing

30

Distortion

an

Rework shaft, obtain proper new shaft and

“A”,

housing, or fit. May housing.

shaft.

Remachine stress. May

shaft require

in housing outer ring.

Remachine stress. May

housing require

Remachine

shaft

with

Conditions

one

both, to require

fillet to shoulder

relieve collar.

fillet to shoulder

relieve collar.

J

26

of

shaft seals.

bearing

shoulder

shoulder


seals.

Remachine

housing


shoulder

to

clear

“A”,

seal.

Condition

to clear

“B”,

28

seal.

Condition

having

2 I -52

30

proper

bore.

REPLACEMENTS

neven

Distortion

expansion

of

ARE

TOO

FREQUENT

Remachine

0

-

CornplaIn,

shaft

housin

fillet

sing

“C”

to

fillet

obtain

to

earance stationary

method

Hammer

of

blows

on

of

rotating

seal

to

the

center

eliminate

rubbing.

into

oil

ball level

or roller. oiler with

level

at

when

mountin

standstill Locate sight

must

cup gage.

not

with

exceed

rotation

of

bearing.

of the

lowermost

Replace

constant

Replace fresh

after

seals

thoroughly

lubricant.

bearing.

47

Shaft and housing face of locknut with bearing seat.

50

oversize, causing excessive pansion of bearing inner thus reducing clearance

Bearing

The

mounti bearing.

Excessively worn leather (or composition), or labyrinth seals. Result: lubricant loss; dirt getting

obtain

parts.

Incorrect

44

(Continued)

seat

shoulders out-of-square

diameter

and Remachine

parts

to obtain

squareness.

machined exring, in

Grind and

shaft shaft.

to

get

proper

fit

between

inner

ring

of

bearing

bearing.

53

“Pounding-out” due to soft larged bore ning

of

outer

of housing metal. Result: . . . causing ring

in

bore enspin-

Rebore

housing

bushing

to correct

and

press

steel

bushing

in

bore.

Machine

bore

of

size.

housing.

VIBRATION Complaint Foreign 5

bon, housing.

matter [dirt, etc.) entering

sand, carbearing

Clean design

out bearing to obtain

“D” housing. adequate

Replace protection

worn-out seals of bearing.

or

improve

seal

27

VIBRATION

REASON


7-8 9-41

10

17-l

8

27

29

28

(Continued)

a shroud

shaft

Retighten

adapter

too

not

small.

tightened

sufi-

(or)

See Ihtration-Corn/hint

Metallize

diometer

and

housing,

and

and

regrind

Housing

bore

Rebalance

load

due to starting.9

distribution

on

Carefully surface.

examine Replace

Rework shaft, new shaft and

bending

shoulder of

Inadequate causing

cocking of

Distortion of shaft ring. Uneven expansion ing inner ring.

32

Distortion of ring. Pinching

shaft. in housing outer ring.

and

inner of bear-

housing and of bearing.

Incorrect linear ment of two shafts with two

outer

or angular alignor more coupled or more bearings.

42

Incorrect Hammer

method blows

45

Excessive resulting

clearance in vibration.

46

Vibration

53

“Pounding-out” of housing bore due t0 Soft metal. Result: enlarged bore . . . causing spinning of outer ring in housing.

of

of on

mounting. bearing. in bearing,

machine.

Remachine

housing, housing.

fillet

to

Remachine collar

housing

fillet

See iliustration-Complaint Remachine

shaft

fillet

Remachine

housing

fillet

Correct coupled operate

“C”,

alignment by shimming in straight line--especially on one shaft.

See Ihstration-Complaint Replace with when mounting. Use

bearings

Check Rebore

bushing

balance

new

with

bearing.

recommended

of rotating

housing and press to correct size

steel

May

on

the

require

require

shoulder

collar.

require

shoulder

29

.

3I

proper

. 32

Condition

blocks. when three

Conditions

Rebalance bushing

Be sure shafts are or more bearings

35-36

hammer

internal

ports.

fit.

May

Condition

Don’t

spots

27

stress.

pillow

“A”,

bore.

25-26

Condition

to obtain

See Ihstration-Complaint

proper

fiat

proper

May

proper

“C”,

for

Condition

relieve

having

21-52

obtain

stress.

to obtain

See Mustration-Complaint

one

looking

Conditions

“C”,

17-l 8

with

“C”,

to

fit.

Conditions

to

“C”,

bearing. area of

lubricant.

both,

relieve

See Illustration-Compiaint

matter.

7-8-P-41 -SI

Conditions

rollers,

or

foreign


proper

housing

or

off

on shaft.

“A”,

balls bearing,

shaft

grip

Replace


Inadequate causirig

fresh

“B”,

See Ibstration-Complaint ball or roller (Result of fast

use

firm

throw

Conditions

to obtain

to get

machine.

to

to relieve and shims

“A”,

See Ihtration-Complaint load.

flinger

Check and scrape housing bore Be sure pedestal surface is flat, pillow block base.

Shaft

31

35-36

of

clean

Unequal bearing.

__

Addition

Carefully

Flat on skidding.

25-26

acids, bear-


Unbalanced too’ large.

22

W”

PRACTICAL SOLUTION


Adapter ciently.

21-52

Complafnf

FOR CONDITION

Corrosive agents (water, points, etc.) entering the ing housing.

6

-

any

part

of

bearing

clearances.

machine. in bore.

Machine

bore

of

UNSATISFACTORY

‘%X?

PERFORMANCE Complaint “I?’

OF


PRACTICAL SOLUTION

:ONDIllON

4

Bearings selected with quate internal clearance ditions where external conducted thru shaft, expanding excessively ner ring.

5

Foreign matter (dirt, bon, etc.) entering housing.

6


7-8-9 41-51

10


EQUIPMENT

inadefor conheat is thereby the in-

sand, carbearing

Replacement bearing should have beoring for proper internal clearance. markings have become indistinct.

Clean out seal design

acids, bear-

Addition



bearing housing. to obtain adequate

of

a shroud

and

See Illustration-complaint

Carefully

clean

flinger

bore flat,

is

to

to and

“A”,

housing,

marking as original with SKF if bearing


(or)

Check and scrape housing Be sure pedestal surface pillow block base.

identical Check

throw

use

off

relieve shims

fresh

or

foreign


Conditions

and

seals bearing.

improve

matter.

bearing. area of

7-8-g-41-51

lubricant.

-

16 23-24

17-18

19

Two shaft.


Shaft

diameter

on one expansion.

Back quate

small.

Metallize

bearings shaft

too

Adapter ciently.

not

tightened

Adapter

tightened

sufTi-




Retighten

shaft

regrind to

Loosen sleeve

locknut on shaft

firm

22

Unbalanced too large. Flat on skidding. Unequal

25126

27

Housing

bore

and but

Inadequate causing

causing

Rebalance

ball or roller (Result of fast load

due starting.)

machine.

distribution

to

Carefully surface.

examine Replace

on

Rework shaft, new shaft and

Replace

shoulder of

cocking

of

shaft.

,Remachine

housing, housing.

in

Remachine collar.

outer

housing ring.

shaft

See Ihstration-

fillet

or

or

both,

“C”, to

relieve


fillet

to

to

obtain

Conditions May

Condition

relieve

“C”,

fit. 17-i

8

one

to clamp

having

proper

bore.

21-52

#

or

proper

flat

spots

fit.

May

on

the

require

25-26 require

shoulder

collar.

27

stress.

Condition

sufficiently

19

looking

stress.

“C”,

with

Conditions

rollers,

-Complaint housing

Cor‘dition

housing


shaft.


“A”,

balls bearing.

proper on

Conditions

“A”,


bending

grip



bearing.

Inadequate

29

load.

16-23-24

“B”

See Illustration-Complaint 21-52

Conditions

to obtain

get


excessively.

shims axial

“A”,

and

adapter

housings,using to permit free

May

require

shoulder

29

29

UNSATISFACTORY

PERFORMANCE

OF

EQUIPMENT

-

Comploi~t

“E”

(Continued)

PRACTICAL SOLUTION

Remachine shaft fillet See Illustration-Complaint

Distortion of outer ring. Pinching of

32

housing bearing.

and

Remachine housing See Iilustrafjon-Complain&

to obtain “c”,

fillet

to obtain “C”,

Incorrect linear or angular alignment of two or more coupled shafts with two or more bearings.

Correct alignment by shimming coupled in straight line-especially operate on one shaft. See Iffustration-Complaint “A”,

39

Prong

Remove lockwasher See Illustration-Complaint

42

Incorrect Hammer

method of mounting. blows on bearing.

Replace with when mounting.

45

Excessive resulting

clearance in vibration.

Use

46

Vibration

of

47

Shaft and square

35-36

rubbing

and face with

against

bearing.

in bearing,

machine,

bearings

Check

housing shoulders, of locknut out bearing seat.

of

-straighten “A”,

new

bearing.

with

balance

32

blocks. when three

Conditions

35-36

prong or Condition

parts.

replace 33

hammer

internal


any

with

new

washer.

of

bearing

part

clearances.

Rebalance

machine.

ports

50

Bearing seat diameter machined oversize, causing excessive expansion of bearing inner ring thus reducing clearance in bearing.

Grind

to proper

53

“Pounding-aut” of housing bore due to soft metal. Result: enlarged bore _ . . causing spinning of outer ring in housing.

Rebore housing and press steel bushing in bore. Machine bore of bushing to correct size. If loads are not excessive, tighter fit in housing, without the use of the steel bushing, may correct the trouble.

BEARING

Shaft Adapter ciently.

17-18

diameter not

Knurling of bearing

48

too small. tightened

ON

inner

ring

of

Unsatisfactory plied. When

ond center punching seat on shoft.

bearing

and

shoft.

SHAFT

“F”

Metallize shaft and regrind to obtain proper Retighten adapter to get firm grip on shaft. See Illustration-CompIaint “B”, Conditions

s&i-

because fit is loose,

high spots metallize

ore shaft

fit. I 7-18

flattened when and regrind to

load proper

is apsize.

I

I

HARD

TURNING Complaint

1

squareness.

fit between

IS LOOSE Complain!

obtain

pillow

.

Remachine

shaft

to

proper Condition

Don’t

recommended

of rotating

proper . Condition 3 I

Wrong type of grease ing’ break-down of

or oil causlubricant.

OF SHAFT “G”

Consult reliable lubricant manufacturer for Check SKF Catostructions to determine be used.


HARD DDE 10 IPICA

TURNING

OF

SHAFT

-

Comptolnt

“0”

(Contlnuod) PRACTICAL


SOLUTION

UDlllON

Low oil through lnsuffrcient

2

level. seal.

Loss

grease

of in

Oil level bearing.

lubricant housing.

Using

should

grease,

be lower

just

below

half

of

center pillow

See III~~~lr~.~lif~if--C~~t~t~l~r~~~f “A”.

of

lowest

block

should

Courlilj~JIl

2

ball

or

be

3

Housing packed with grease, or oil level too high . . . causing excessive churning of lubricant, high operating temperature, oil leakage.

Purge bearing until only lower half of housing is grease. Using oil lubrication, reduce level to just lowest ball. 1 ee Ill// ,t11lti/,t(-Cf,t)lplrll111 “A”, Couditiou 9

4

Bearings selected with quate internal clearance ditions where external conducted thru shaft, expanding excessively ner ring.


5

Foreign matter (dirt, bon, etc.) entering housing.

6


‘/s

roller to

t/2 to below

in

‘h

full.

sh full center

of of

-_

7-8 9-41

51

Housing HousiLg tortion housing

inadefor conheat is thereby the in-

sand, carbearing

Clean seal

acids, bear-

Addition


10


12

Leather or with excessive dried out.

13

composition seals spring tension or

13-40

Rotating stationary

seals rubbing parts.

15

Opposed

mounting.

against

out design

bearing housing. to obtain odequate

of

a shroud

and

Carefully

clean

Replace spring

leather tension.

housing,

13-24

19

Two shaft.

Adapter


Check Correct

of

See Illustratjon-Complajllt

tightened

on one expansion.

Back quate

between bearing.

housing


locknut on shaft

and but

See Illustration-Complaint 39

Prong

rubbing

against

bearing.

Remove

-

lockwasher.

See Illwrtratiom-Complaint

“A”, Straighten

ones

seal

to

bearing. area of

I

rubbing.

to

relieve

oxial

shims to obtoin adeoxial bearing motion.

16-23-24


or

reduced

II

Conditions

Condition

eliminate

flange

using free

Condition

having

I j-33-40

cover

housings, to permit

prong

“A”,

I-I

matter.

12

Conditiarz


improve

foreign


with

Condition

“A”,

or

original bearing

lubricant.

rotating

and

off

7-8-p-4

Cntlditiorz

“A”,


fresh

se.ais bearing.

throw

relieve shims

seals

“A”,

See Illustration-Complaint Loosen sleeve

excessively.

use

.‘A*’

of

to and

or composition Lubricate seals.

running clearance alignment.

to

Conditions

See IIIrfstr~rtinn-Conlplrlint

Insert gasket pre-loading

bearings shaft

bore flat,

and

See Illustration-Complaint 16

flinger

“A”,




[or)

Check and scrape housing Be sure pedestal surface is pillow block base.

identical Check

sufficiently

to

clamp

I9 replace

with

new

washer.

19.

31

: HARD

RR&OH

causing

roll

of

OF

SHUT

-

CornplaInt

“0”

(Continmd!

C0NolYloN

bending

Distortion

TURNING

of

bearing

shaft.

seals.

shimming n-specially

Shaft

earing

and

seat

housing

shoulders,

diameter

machined Grind

32

shaft

to

get

proper

pillow

fit

blocks. when three

between

inner


ring

of bearing

l

ATLANTA, GA

680 A - Wharton Circle, S W P 0 Box 43845 Atlanta, GA 30336 Telephone - 404-696-7750

BIRMINGHAM, AL Suite 218 1 Riverchose Office Plaza Birmingham, AL 35244 Telephone - 205-988-4232 BOSTON, MA Telephone - 617-872-4643 BUFFALO, NY Suite 103 2777 Sheridan Drive Tonawanda, NY 14150 Telephone - 716-837-5244 CHARLOTTE, NC Suite 214 5501 Executive Center Drive Charlotte, NC 28212 Telephone - 704-568-5500 CHICAGO, IL Suite 320 2 Crossroads of Commerce Rolling Meadows, IL 60008 Telephone - 312-992-3732

l

SKF INDUSTRIES, INC BEARINGS GROUP 1100 First Avenue King of Prussia, PA 19406 Telephone - 215265-1900

INDIANAPOLIS, IN Suite G-102A 2346 S Lyndhurst Drive Indianapolis, IN 46241 Telephone - 317-248-0702

- RENO, NV Warehouse) !3 00 Edison Way. P 0 Box 10303 Reno. Washce CountY. NV 89502 Telephone - 702-323-0311 RICHMOND, VA Suite 105 Courtside at Brandermill 13630 Genito Road Midlothian. VA 23113 Telephone - 804-744-3900

MEMPHIS, TN Suite 202 3Odf Getwell Road Memphis, TN 38118 Telephone - 901-795-5580

ST. LOUIS, MO Suite 304. Clayton Plaza BIG 7750 Clayton Road St Louis, MO 63117 Telephone - 314X47-3444

MILWAUKEE, WI 2401 N. Mayfair Road Milwaukee, WI 53226 Telephone - 414-771-9920

CLEVELAND, OH 21403 Chagrrn Blvd.. Room 104 Beachwcod, OH 44122 Telephone - 216-491-9200

NEW YORK, NY 409 Minnisink Road Totowa. NJ 07512 Telephone - 201-255-0864

DALLAS, TX 2246-52 Vanta e Street Dallas, TX 7520 ‘3 Telephone - 214-631-0831

ORLANDO, FL Surte 159 One Purlieu Place Winter Park, FL 32792 Telephone - 305-678-4100

DETROIT, Ml Suite 200 21650 W. Eleven Mile Road Southfield. Ml 48076 Telephone - 313-353-5255

QUAD CITIES Suite 223, Brenton Bank Bldg Davenport, IA 52803 Telephone - 319-322-7105

LOS ANGELES, CA Suite 128 32107 Lindero Canyon Rood Westlake Village, CA 91361 Telephone - 213-991-9770

MINNEAPOLIS. MN Suite 546. Southtown Office Park 8120 Penn Avenue. south Bloomington, MN 55434 Telephone - 612-884-2402

- Stock corned at these lbcatrons

II81 20M GP

HOUSTON, TX Suite 126 4420 FM 1960 West Houston, TX 77068 Telephone - 713-440-3914

CINCINNATI, OH Suite 3 - Colony Square 7770 Cooper Road Cincinnati, OH 45242 Telephone - 513-793-1990

DENVER, CO Suite 118 2305 E Arapahoe Road Littleton, CO 80122 Telephone - 303-794-8795

PORTLAND, OR Suite 235 8835 SW Canyon Lane Portland, OR 97225 Telephone - 503-297-1751

HARTFORD. CT 750 Old Main Street Rocky Hill, CT 06067 Telephone - 203-529-6871

PHILADELPHIA, PA Suite 1109 996 O l d S c h o o l R o a d Wayne, PA Eagle 19087 Telephone - 215-688-7775 PITTSBURGH. PA 9800 McKnight Road Pittsburgh, PA 15237 Telephone - 412-931-2955

SALT LAKE CITY, UT Suite 13 1270 East 8600 South Sandy. UT 84070 Telephone - 801~566-4281 SAN FRANCISCO, CA Suite 206 150 N Wiget Lane Walnut Creek, CA 94598 Telephone - 415-943-1800 SEATTLE, WA Suite 102 14042 N E 8th Ave Bellevue. King Co, WA 9800; Telephone - 206-746-6710 l

YOUNGSTOWN, OH (Warehouse) 100 Victoria Road P 0 Box Drawer D Youngstown, OH 44515 Telephone - 216-799-1561 AUTOMOTIVE DIVISION Suite 220 6735 Telegraph Road Birmingham, Ml 48010 Telephone - 313-644-9171

~ Application Report Uq %U

600

No.592

U- ,4td/p ta . . .

DETERMINE THE CONDITION OF

ANTI-FRICTION BEARINGS

by Robert E. Ellis Balancing & Consulting Service Manager IRD Corporation

INTERNATIONAL R E S E A R C H A N D D E V E L O P M E N T C O R P O R A T I O N Subsidiary

of

H. H. Robertson Co.

6150 Huntley Road, Worthington, Ohio

(Col u mbus )

Phone 885-5376

’

Using IRD Model 600 Vibration Analyzer to DETERMINE T HE CONDITION OF ANTI-FRICTION BEARINGS How do you know when bearings are worn and need ? Many times the answer is obvious to be replaced because of machine failure, poor quality in finished parts, and unscheduled downtime. When you dismantle you may find pits in the raceways or on the balls or rollers. You may find flaked areas, discoloration, broken retainers, dirt, corrosion, and a host of others. If a faulty bearing is continued in operation it always gets worse, never better. The whole machine may become noisy, the shaft may become loose and other parts of the machine may fail.

perpendicular to shaft axis orthe shaft is not in line with the housing.

b) Angular and/or offset misalignment be-

tween different machine components of a system, such as a motor driving a fan through a gear box. This condition refers to misalignment between motor and gearbox or gearbox and fan, and occurs when the shaft axis is not parallel to the axis tbrough the bearing centers.

2) Dirt or Foreign Matter-dirt or metal part-

icles in the lubricant or from flaking will be Bearings with pitted or rough raceways and balls pressed between the rolling elements of the impose forces on the cages when the rolling elebearing and the raceway causing forces that ments the rough spots. These forces show produce indentation and pits. up as vibration in the machine structures. It is 3) Lack of Lubrication-A dry bearing may prothese forces that result in decreased bearing life, vide excessive heat, rubbing bearing disfatigue failure, heat and noise. Eventually, the tortion showing up as vibration. bearings become unserviceable. It is also these forces that allow us to detect the bearings’ condi4) Corroded Parts-can start from: rust, oxition through vibration analysis before a costly dation of lubricant, contaminating influence. failure occurs. In many cases the minute vibrations present in a machine structure close to the 5) Pits-can be caused by corrosion or electribearing contain the information needed to detercal arcing. Electrical leakage may occur mine the bearing’s condition. Vibration is often through bearings from static electricity on a good indicator of bearing performance. A high line shafts and in direct current motors. vibration level can indicate damage by unbalance Sparking at regular intervals burns away or misalignment, excessive radial or axial load, metal leaving holes and pits. dirt and corrosion, or brinelling in assembly. 6) Lack of Concentricity-usually becomesapThe IRD Vibration Analyzer can be used to anaparant only at a low level of vihration-may lyze these and other vibrations so that a rapid show up as vibration at rotor speed. The evaluation of the bearing’s condition may be obcharacteristics are such that it acts like tained and corrective action taken if needed. unbalance which shows up on one radial dirCauses of Bearing Vibration ection (horizontal, vertical, or at some other specific angle). The equipment can generSources of vibrations in bearings are: ally be balanced to a low level of vibration 1) Misalignment-two kinds in one direction but will not show a low a) Angular misalignment between inner and level of vibration in another. outer races-the bearing rotates with the inner ring at an angle to the shaft axis, 7) Pinch and Overload-bearings installed in the balls will wear a track which wobout-of-round housings or on out-of-round bles from one side of the raceway to the shafts may distort enough to cause vibration other. Common causes of this condition overload, and failure. Early fatigue failure are: shoulder out-of-square, burr between at opposite sides of the raceways may result. the shoulder and bearing and fillet too large. 8) Bearing-Retainer Rattle-loose retainers may be a source of vibration. Misalignment difficulties can also arise 9) Excessive Clearance-mostly found in sleeve when bearing housing shoulders are not

bearings. Can be detected by the difference in amplitude readings taken on the bearing housing and on the shaft. Shaft readings are obtained by measuring directly on the shaft running in the bearing, using a shaft stick.

10) Cracks in Rings and Parts-damage that has occurred during installation through excessive force, hammering or forcing the bearing onto a tapered seat.

Analyzing Bearing Faults with the Model 600

M a k e all vibration measurements directly on the bearing housing as close to the bearing moving parts as possible. One exception is when making direct

Things to look for when analyzing bearing vibration: Filter Out

1) Small erratic increases and decreases in amplitude meter reading. May be random or periodic. Amount of vibration will depend on severity of fault.

Many of the above conditions will show vibrations in the axial direction on pre-loaded bearings. A rough anti-friction bearing where the roughness js due to pits, holes, dirt, etc., results in a relative high frequency of vibration. The vibration frequency may be several times the frequency of the rotating member which is mounted in the bearing. The frequency of vibration may not be a direct multiple of the shaft speed.

Unbalance

and

Critical

Speeds

Both unbalance and operation at critical speed will cause a rotating radial load, which consumes some of the bearing’s capacity and which, if excessive, can lead to beoring failure. Balancing is essential ; and limits should be set such that the unbalance load on the bearing is not more than one-tenth of the bearing capacity at speed. Ball bearings will sometimes operate for limited periods of time at or near a shaft critical speed, provided that the critical speed is low. The effect of operation at a critical speed is unpredictable because of the unknown damping factors, and it is, therefore, best to keep the shaft critical speed either well above operating speed or well below it. High vibrations on bearings that are misaligned, overloaded, etc., will show high frequency characteristics as noted above.

or

forces due to unbalance of rotating parts

misalignment

2) Apparent erratic or multiple firing of the

strob lamp. Reference mark on the shaft will appear at several positions. May occur as a multiple image slowly rotating. Strob pattern appears related to s h a f t s p e e d . 3)

Apparent erratic frequency meter readings. Generally, the frequency meter will indicate a much higher frequency than shaft speed. Often the best frequency indications are obtained using the velocity position.

Filter In 1) Steady

vibration displacement or velocity readings-low amplitude-high frequencyfrequency indications not a direct multiple of shaft speed. Velocity measurements usually most useful.

2) Steady frequency meter indications at high speeds. May or may not be direct multiples of the shaft speed.

3) Variable

vibration

amplitude

readings-rel-

atively low amplitude-high frequency. Amplitude readings “beats” or slowly varies up and down. Frequency meter steady. Frequency may or may not be a direct multiple of the shaft speed.

The vibrations due to rough bearings are easily distinguished from high frequency electrical vib-

CAUTION L arge

shaft measurements using the shaft stick.

moy

mask

many

bearing

bles. Unbalance, misalignment, loose, damaged parts must be corrected before

trouand bear-

ing analysis i s a t t e m p t e d . Balance the rotating parts to a low vibration level if required.

The information given below describes the use of the IRD Model 600 Vibration Analyzer for analyzing bearing faults.

rations . Vibrations due to rough hearings will continue after the electrical power has been shut off and while the rotating member is coasting toa stop. Vibrations from electrical causes, however, will cease immediately when the electrical power is shut off.

Use of an Oscilloscope An Oscilloscope connected to the scope outlet jack of the IRD Vibration

Analyzer will allow

a

direct visualobservation of the bearing vibration pattern as measured at the pickup location. The presence of high frequency noise and hash, spikelike pulses or erratic and rapid changes in amplitude are bearing condition indicators. Either displacement or velocity may be used but velocity measurements usually give better high frequency indications The higher the speed, the more sensitive the bearing is to theadverse effects of misalignment, poor lubrication, improper fitting practice, poor heat dissipation and contamination.

-

IRD #592

DO’S AND DON’T’S FOR BEARINGS . . . assembly, maintenance, inspection and lubrication Do work as close to the ideal conditions pictured here.

Don’t work under the handicap of poor tools, rough

Dividends

bench,

DO

work

DO

in

with

remove

exposing

DO

beoring

clean all

performance

tools,

outside

in

will

clean

dirt

result.

housing

before

bearings.

handle

dry

hands.

DO treat a used bearing as carefully as a

new one.

DO use clean solvents and hushing oils.

DO lay bearings out on clean paper.

DO

use

DO

keep

disassembled

bearings

from

dirt

and

lint-free

bearings

rags

wrapped

if

beorings

in

are

oil-proof

wiped.

paper

when

not in use.

clean

inside

DO

install

new

of

housing

bearings

as

before

replacing

removed

DON’T

use

dirty,

DON’T

handle

DON’T

spin

DON’T

spin

brittle

bearings

uncleaned

any

or

chipped

with

dirty,

tools.

moist

hands.

bearings.

bearings

with

compressed

air.

DON’T use same container for cleaning and final of

DON’T use bearings.

bearings.

cotton

waste

or

dirty

cloths

to

from

bearings. packages,

time.

DON’T

scratch

or

nick

DON’T

remove

grease

DON’T

use

bearing

surfaces.

washing.

DO keep bearing lubricants

or

oil

from

new

kind

or

amount

bearings.

clean when applying and

cover containers when not in use.

14

or work on rough or dirty

wipe

DON’T expose bearings to moisture or dirt at any

DO

without

DON’T use wooden mallets

rinsing

clean,

dirt.

bench tops.

with-clean,

DO protect moisture.

of

DON’T work in dirty surroundings.

surroundings.

from

plenty

incorrect

of

lubricant.

The illustrations below identify the bearing parts of the eight SKF basic bearing types. The used conform with the terminology H -, section of the AFBMA’ Standards - a n d are mutually accepted by the anti-friction bearing manufacturers. *Anti-Friction

Bearing

Manufocturcr

Association,

Inc.

WN.,,,

.-

i

1

S e l f Alrgnrng 6oll Bearing

Double Row Deep Groove Ball Bearing

Single Row D e e p Graove B o l l Eeorrng

Spherd Roller Beormg

Cyhndrrco/ Roller Benrtng

AT a p e r e d RoNer h7rrng

E Type Spherical R o l l e r Thrust

Spherical

Thrurl 1 Inner Ring 2 Inner Ring Corner 3. Inner Ring Land 4 Outer Ring Lond 5. Outer Ring 6. Ball 7. Counter Bore 8. Thrust Face

4

9 Outer Ring Roceroy 10 Inner R i n g Raceroy I I Outer Ring Corner 12 Spherical Roller 13 Lubrication Feature (Hole and Groor.) (W33l 14 Spherical O u t e r Ring Roteray I5 Floating Guide Ring 16 Inner Ring Face

17 18 I9 20 21 22 23 24

Roller

Bearing

Ouler Ring F a c e Cylindrical R o l l e r Outer Ring Rib Cone Front Face Cone F r o n t Face R i b Cup (Outw Ring) Tapered Roller Cone Back Face Rib

25 Cone Bock Pace 26. Under Cut 27. Cone (Inner Ring) 28. cage 29. Cogs 30. Face 31 Cage G u i d e Sleeve 32. Shoft Washer (Inner Ring) 33. Housing Washer (Outer Ring)

Skf Roller Bearing Handbook.pdf 33071

Overview 4q3b3c

More details 26j3b

Related Documents 171j1w

Skf Roller Bearing Handbook.pdf 33071

Skf Roller Bearing Catalogue p3f3x

Skf Bearing Beacon.pdf 5f4f1b

Skf Bearing Calculator 1n4ow

Skf Bearing Select 3v4wq

Skf Bearing Pricelist 2017 4t3g4z