3 Angular contact ball bearings - SKF.com

62 Pages·2013·1.42 MB·English

3 Angular contact ball bearings
Designs and variants . . . . . . . . . . . . . . 476 Design of bearing arrangements . . . . 498
Single row angular contact Single row angular contact
ball bearings . . . . . . . . . . . . . . . . . . . . . . 476 ball bearings . . . . . . . . . . . . . . . . . . . . . . 498
Basic design bearings . . . . . . . . . . . . . 477 Proper adjustment . . . . . . . . . . . . . . . 498
Bearings for universal matching . . . . 477 Axial loads in one direction . . . . . . . . . 498
Double row angular contact Load ratio . . . . . . . . . . . . . . . . . . . . . . 498
ball bearings . . . . . . . . . . . . . . . . . . . . . . 478 Four-point contact ball bearings . . . . . . 499
Basic design bearings . . . . . . . . . . . . . 479 Used as a thrust bearing . . . . . . . . . . 499
Bearings with a two-piece inner ring . 479 Vertical shafts . . . . . . . . . . . . . . . . . . . 499
Four-point contact ball bearings . . . . . . 480 Load ratio . . . . . . . . . . . . . . . . . . . . . . 499
Cages . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481
Sealing solutions . . . . . . . . . . . . . . . . . . 482 Designation system . . . . . . . . . . . . . . . 504
Shields . . . . . . . . . . . . . . . . . . . . . . . . . 482
Contact seals . . . . . . . . . . . . . . . . . . . . 482 Product tables
Greases for capped bearings . . . . . . . 483 3.1 Single row angular contact
Locating slots . . . . . . . . . . . . . . . . . . . . . 484 ball bearings . . . . . . . . . . . . . . . . . . 506
3.2 Double row angular contact
Performance classes . . . . . . . . . . . . . . 485 ball bearings . . . . . . . . . . . . . . . . . . 522
SKF Explorer bearings . . . . . . . . . . . . . . 485 3.3 Capped double row angular
SKF Energy Efficient (E2) bearings . . . . 485 contact ball bearings . . . . . . . . . . . 526
3.4 Four-point contact ball bearings . . 530
Bearing data . . . . . . . . . . . . . . . . . . . . . 486
(Dimension standards, tolerances, Other angular contact ball bearings
contact angle, internal clearance, Bearings with Solid Oil . . . . . . . . . . . . . . 1185
preload, misalignment, friction, starting SKF DryLube bearings . . . . . . . . . . . . . . 1191
torque, power loss, defect frequencies) NoWear coated bearings . . . . . . . . . . . . 1241
Super-precision
Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . 492 bearings . . . . . . . . † skf .com/super-precision
(Minimum load, equivalent loads) Hybrid bearings . . † skf .com/super-precision
Load carrying capacity of
bearing pairs . . . . . . . . . . . . . . . . . . . . . 494
Calculating the axial load for bearings
mounted singly or paired in tandem . . . 495
Temperature limits . . . . . . . . . . . . . . . 497
Permissible speed . . . . . . . . . . . . . . . . . 497
475
3 Angular contact ball bearings
Designs and variants Fig. 1
Angular contact ball bearings have raceways
in the inner and outer rings that are displaced
with respect to each other in the direction of
the bearing axis . This means that they are
designed to accommodate combined loads, i .e .
simultaneously acting radial and axial loads .
The axial load carrying capacity of angular
contact ball bearings increases with increasing
contact angle . The contact angle is defined as contact
angle
the angle between the line joining the points of
contact of the ball and the raceways in the
radial plane, along which the load is transmit-
ted from one raceway to another, and a line
perpendicular to the bearing axis († fig. 1) .
SKF angular contact ball bearings are
manufactured in a wide variety of designs and
sizes . The most commonly used designs are: Angular contact ball bearings listed in this cata-
logue constitute the basic SKF assortment and
• single row angular contact ball bearings are only part of the total assortment . Other
• double row angular contact ball bearings SKF angular contact ball bearings include:
• four-point contact ball bearings
• Super-precision angular contact ball
bearings
For additional information, refer to the
product information available online at
skf .com/super-precision .
• Thin section angular contact ball bearings
For additional information, contact the
SKF application engineering service .
More information
• Hub bearing units
Bearing life and load ratings . . . . . . 63 Information about these products can be
supplied on request .
Design considerations . . . . . . . . . . . 159
Bearing systems . . . . . . . . . . . . . . . . 160 Angular contact ball bearings with a larger
Recommended fits . . . . . . . . . . . . . . . 169 size than those listed in the product tables are
Abutment and fillet dimensions . . . . 208 available on request . For information about
these bearings, refer to the product informa-
Lubrication . . . . . . . . . . . . . . . . . . . . 239 tion available online at skf .com/bearings, or
contact the SKF application engineering service .
Mounting, dismounting and
bearing care . . . . . . . . . . . . . . . . . . . 271
Single row angular contact ball bearings
Mounting instructions for individual
bearings . . . . . . . . . . . . . † skf .com/mount SKF single row angular contact ball bearings
(† fig. 2) can accommodate axial loads in one
direction only . A single row bearing is typically
adjusted against a second bearing .
The bearings are non-separable and the
bearing rings have one high and one low shoul-
der . The low shoulder enables a large number
of balls to be incorporated in the bearing, giving
it a relatively high load carrying capacity .
476
Designs and variants
The standard assortment of SKF single row Fig. 2
angular contact ball bearings comprises bear-
ings in the 72 B(E) and 73 B(E) series . Some
sizes in the 70 B series are also available . 3
Matrix 1 († page 500) provides an overview
of the standard assortment . In addition, SKF
single row angular contact ball bearings are
available in many other designs, dimension
series, and sizes . For additional information,
refer to the product information available
online at skf .com/bearings .
Basic design bearings
Basic design bearings are intended for
arrangements where only one bearing is used
at each bearing position . They have Normal
tolerances concerning bearing width and stand-
out of the rings . Therefore, they are not suit-
able for mounting immediately adjacent to
each other .
Bearings for universal matching
Bearings for universal matching are intended
to be used in sets . The width and the standout
of the rings are manufactured to close toler-
ances . When two bearings are mounted
immediately adjacent to each other, a given
internal clearance or preload or an even load
distribution between the two bearings is
obtained without the use of shims or similar
devices .
Bearings for universal matching can also be
beneficial in arrangements with single bear-
ings . Most bearings belong to the SKF Explorer
performance class and as such have higher
precision, increased load carrying capacity
and speed capability .
Bearings for universal matching in the
72 B(E) and 73 B(E) series are identified by the
suffix CA, CB or CC for internal clearance or
GA, GB or GC for preload . Bearings for univer-
sal matching in the 70 B series are identified
by the suffix G for clearance . When ordering,
indicate the number of individual bearings
required and not the number of sets .
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3 Angular contact ball bearings
Paired mounting Double row angular contact ball bearings
Paired mounting can be done in three ways SKF double row angular contact ball bearings
(† fig. 3): († fig. 4) correspond in design to two single
row angular contact ball bearings arranged
• Tandem arrangement back-to-back, but take up less axial space .
A tandem arrangement is used when the They can accommodate radial loads as well as
load carrying capacity of a single bearing is axial loads in both directions . They provide
inadequate . When arranged in tandem, the stiff bearing arrangements and are able to
load lines are parallel and the radial and axial accommodate tilting moments .
loads are equally shared by the bearings . The standard assortment of SKF double
However, the bearing set can accommodate row angular contact ball bearings comprises
axial loads in one direction only . If axial bearings in the 32 A, 33 A and 33 D series .
loads act in both directions, a third bearing, Matrix 2 († page 501) provides an overview
adjusted against the tandem pair, must be of the standard assortment . For information
added . about other double row angular contact ball
• Back-to-back arrangement bearings, refer to the product information
Mounting two bearings back-to-back pro- available online at skf .com/bearings .
vides a relatively stiff bearing arrangement, Bearings in the 52 and 53 series, in
which can also accommodate tilting ac cordance with ABMA standards, are no
moments . When arranged back-to-back, longer available from SKF and have been
the load lines diverge towards the bearing replaced with 32 and 33 series bearings in
axis . Axial loads in both directions can be accordance with ISO . With the exception of
accommodated, but only by one bearing in size 3200, 32 and 33 series bearings are
each direction . dimensionally interchangeable with bearings
• Face-to-face arrangement in the 52 and 53 series . Size 3200 has a width
Mounting two bearings face-to-face is not of 14 mm instead of 14,3 mm .
as stiff as a back-to-back arrangement,
but less sensitive to misalignment . When
arranged face-to-face, the load lines con-
verge towards the bearing axis . Axial loads
in both directions can be accommodated,
but only by one bearing in each direction .
Fig. 3
Tandem Back-to-back Face-to-face
arrangement arrangement arrangement
478
Designs and variants
Basic design bearings Fig. 4
Basic design bearings (designation suffix A)
have an optimized internal geometry to provide
high radial and axial load carrying capacity and 3
quiet operation . Basic design bearings that are
also available capped may have recesses in the
inner and outer rings († fig. 5) .
Bearings with a two-piece inner ring
Bearings with a two-piece inner ring († fig. 6)
incorporate a large number of large balls, giv-
ing the bearing its high load carrying capacity,
especially in the axial direction .
Bearings in the 33 D series are separable, i .e .
the outer ring with ball and cage assemblies
can be mounted independently of the inner
ring halves .
Bearings in the 33 DNRCBM series are non-
separable . They have a snap ring groove with Fig. 5
a snap ring in the outer ring, enabling simple
and space-saving axial location in the housing .
Bearings in the 33 DNRCBM series have been
designed specifically for centrifugal pumps,
but can also be used in other applications .
Fig. 6
33 D 33 DNRCBM
479
3 Angular contact ball bearings
Four-point contact ball bearings Fig. 7
Four-point contact ball bearings († fig. 7)
are radial single row angular contact ball
bearings with raceways that are designed to
support axial loads in both directions . For a
given axial load, a limited radial load can be
supported († Load ratio, page 499) . These
bearings take up considerably less axial space
than double row bearings .
The inner ring is split . This enables a large
number of balls to be incorporated in the bear-
ing, giving the bearing its high load carrying
capacity . The bearings are separable, i .e . the
outer ring with ball and cage assembly can be
mounted separately from the two inner ring
halves .
Both inner ring halves of SKF Explorer four-
point contact ball bearings have a recessed
shoulder . This improves oil flow when the Table 1
bearing is used together with an SKF cylin-
drical roller bearing († fig. 12, page 499) . In Cages for single row angular contact ball bearings Cages for double row angular contact ball bearings Cages for four-point
Standard assortment † matrix 1, page 500 Standard assortment † matrix 2, page 501 contact ball bearings
addition, these recesses can be used to facili- Standard assortment
tate dismounting . † matrix 3, page 502
The standard assortment of SKF four-point
contact ball bearings comprises bearings in
the QJ 2 and QJ 3 series . Matrix 3
(† page 502) provides an overview of the
standard assortment . For information about
other four-point contact ball bearings, refer
to the p roduct information available online
at skf .com/bearings .
Cage Window-type, ball centred Window-type, Window-type, Snap-type, Snap-type, Snap-type, Window-type, Prong-type, Window-type, Window-type,
type ball centred ball centred ball centred ball centred crown, ball ball centred outer ring outer ring lubrication
centred centred centred grooves in
the guiding
surface, outer
ring centred
Material PA66, PEEK, Stamped brass, Machined PA66, Stamped Stamped Machined Machined Machined PEEK,
glass fibre glass fibre stamped steel1) brass, glass fibre steel steel brass brass brass glass fibre
reinforced reinforced machined reinforced reinforced
steel1)
Suffix P PH Y, J1) M, F1) TN9 – – M MA MA PHAS
1) Check availability prior to ordering
480
Designs and variants
Cages
The lubricants generally used for rolling
Depending on their design, series and size, bearings do not have a detrimental effect on
SKF angular contact ball bearings are fitted cage properties . However, some synthetic oils
with one of the cages shown in table 1 . Double and greases with a synthetic oil base and 3
row bearings are equipped with two cages . The lubricants containing a high proportion of EP
stamped steel cage in double row bearings is additives, when used at high temperatures,
not identified in the bearing designation . For can have a detrimental effect on polyamide
information about the availability of cages for cages . For additional information about the
the various bearing designs, series and sizes, suitability of cages, refer to Cages († page 37)
refer to matrices 1 to 3 († pages 500 to and Cage materials († page 152) .
502) .
Table 1
Cages for single row angular contact ball bearings Cages for double row angular contact ball bearings Cages for four-point
Standard assortment † matrix 1, page 500 Standard assortment † matrix 2, page 501 contact ball bearings
Standard assortment
† matrix 3, page 502
Cage Window-type, ball centred Window-type, Window-type, Snap-type, Snap-type, Snap-type, Window-type, Prong-type, Window-type, Window-type,
type ball centred ball centred ball centred ball centred crown, ball ball centred outer ring outer ring lubrication
centred centred centred grooves in
the guiding
surface, outer
ring centred
Material PA66, PEEK, Stamped brass, Machined PA66, Stamped Stamped Machined Machined Machined PEEK,
glass fibre glass fibre stamped steel1) brass, glass fibre steel steel brass brass brass glass fibre
reinforced reinforced machined reinforced reinforced
steel1)
Suffix P PH Y, J1) M, F1) TN9 – – M MA MA PHAS
1) Check availability prior to ordering
481
3 Angular contact ball bearings
Sealing solutions
SKF double row angular contact ball bear-
SKF supplies the most common basic design ings with a shield on both sides are identified
double row angular contact ball bearings by the designation suffix 2Z .
capped with a contact seal or shield on both
sides († matrix 2, page 501) . For additional Contact seals
information about the suitability of seals or Contact seals († fig. 9) are made of NBR and
shields under various conditions, refer to are reinforced with a sheet steel insert . These
Sealing solutions († page 226) . seals, which are fitted in a recess on the outer
Bearings capped on both sides are lubricated ring, make good, positive contact with the
for the life of the bearing and should not be recess . The seal lip exerts light pressure
washed or relubricated . The bearings are con- against the recess on the inner ring to provide
sidered maintenance-free . If they are to be hot an effective seal .
mounted, an induction heater should be used . SKF double row angular contact ball bear-
SKF does not recommend heating capped ings with a contact seal on both sides are iden-
bearings above 80 °C (175 °F) . However, if tified by the designation suffix 2RS1 .
higher temperatures are necessary make sure
that the temperature does not exceed the per-
missible temperature of either the seal or
grease, which ever is lowest . During start-up,
grease may leak at the inner ring . For bearing
arrangements where this would be detrimental,
special design steps must be undertaken . For
additional information, contact the SKF appli-
cation engineering service .
Shields
Shields are made of sheet steel . SKF supplies
shields in two designs . The shields used in
smaller bearings have an extension in the
shield bore to form a long, narrow gap with the
land of the inner ring shoulder († fig. 8a) .
The shields used in larger bearings and in all
SKF Explorer bearings extend into a recess on
the inner ring († fig. 8b) .
Fig. 8 Fig. 9
a b
482
Designs and variants
Greases for capped bearings
Capped double row angular contact ball bear-
ings are filled with one of the following greases
(† table 2): 3
• The standard grease is GJN .
• In Europe, MT33 is commonly used and
widely available .
• SKF Energy Efficient angular contact ball
bearings are filled with the low-friction
grease GE2 .
• Other greases listed in table 2 can be
supplied on request .
The standard grease is not identified in the
bearing designation (no designation suffix) .
Other greases are indicated by the corres-
ponding grease suffix .
–50 0 50 100 150 200 250 °C
Table 2
Technical specifications of SKF standard and special greases for capped double row angular contact ball bearings
Grease Temperature range1) Thickener Base NLGI Base oil viscosity [mm2/s]
oil type consistency at 40°C at 100 °C
class (105 °F) (210 °F)
–5 0 0 50 100 150 200 250 °C
GJN Polyurea Mineral 2 115 12,2
soap
MT33 Lithium Mineral 3 100 10
soap
VT113 Lithium Mineral 3 113 12,1
complex paraffinic
WT Polyurea Ester 2-3 70 9,4
soap
GWF Diurea Synthetic 2-3 67,5 9,6
SHC/ether
GE2 Lithium Synthetic 2 25 4,9
soap
–60 30 120 210 300 390 480 °F
–60 30 120 210 300 390 480 °F
1) Refer to the SKF traffic light concept † page 244
483