Super-precision angular contact ball bearings: High-speed, E design

52 Pages·2013·1.89 MB·English

Super-precision angular
contact ball bearings:
High-speed, E design
719 .. E (VEB) and 70 .. E (VEX) series
Contents
A C
Product information Product data
SKF super-precision angular contact ball Bearing data – general . . . . . . . . . . . . 18
bearings in the 719 .. E (VEB) and Boundary dimensions . . . . . . . . . . . . . 18
70 .. E (VEX) series . . . . . . . . . . . . . . . 3 Tolerances . . . . . . . . . . . . . . . . . . . . . . 19
Bearing preload . . . . . . . . . . . . . . . . . . 19
The assortment . . . . . . . . . . . . . . . . . 4 Bearing axial stiffness . . . . . . . . . . . . . 24
High-speed, E design bearings . . . . . . . 4 Fitting and clamping bearing rings . . . . 26
Bearing series . . . . . . . . . . . . . . . . . . . 6 Load carrying capacity of bearing sets . 27
Bearing variants . . . . . . . . . . . . . . . . . . 6 Equivalent bearing loads . . . . . . . . . . . 27
Single bearings and matched Attainable speeds . . . . . . . . . . . . . . . . . 28
bearing sets . . . . . . . . . . . . . . . . . . . . . 7 Cage . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Seals . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Applications . . . . . . . . . . . . . . . . . . . . 8 Materials . . . . . . . . . . . . . . . . . . . . . . . 29
Heat treatment . . . . . . . . . . . . . . . . . . . 29
Marking of bearings and bearing sets . . 30
B
Recommendations Packaging . . . . . . . . . . . . . . . . . . . . . . . 31
Designation system . . . . . . . . . . . . . . . 31
Bearing arrangement design . . . . . . . 10
Single bearings . . . . . . . . . . . . . . . . . . 10 Product tables . . . . . . . . . . . . . . . . . . 34
Bearing sets . . . . . . . . . . . . . . . . . . . . 10
Type of arrangement . . . . . . . . . . . . . . 11
D
Application examples . . . . . . . . . . . . . . 12 Additional information
Lubrication . . . . . . . . . . . . . . . . . . . . . 14 Setting the highest standard for
Grease lubrication . . . . . . . . . . . . . . . . 14 precision bearings . . . . . . . . . . . . . . . 46
Oil lubrication . . . . . . . . . . . . . . . . . . . . 15 Super-precision angular contact ball
bearings . . . . . . . . . . . . . . . . . . . . . . . . 46
Super-precision cylindrical roller
bearings . . . . . . . . . . . . . . . . . . . . . . . . 47
Super-precision double direction angular
contact thrust ball bearings . . . . . . . . . 47
Super-precision angular contact thrust
ball bearings for screw drives . . . . . . . . 47
SKF – the knowledge engineering
company . . . . . . . . . . . . . . . . . . . . . . . 50
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SKF super-precision angular contact
A
ball bearings in the 719 . . E (VEB)
and 70 . . E (VEX) series
Machine tools and other precision applica- The bearings are characterized by:
tions require superior bearing performance .
Extended speed capability, a high degree of • very high speed capability
running accuracy, high system rigidity, low • high degree of stiffness
heat generation, as well as low noise and • relatively high load carrying capacity
vibration levels are just some of the per- • extended bearing service life
formance challenges . • low heat generation
To meet the ever-increasing performance • compact cross section
requirements of high-speed precision appli-
cations, SKF has developed super-precision Bearings in the 719 . . E (VEB) and 70 . . E
bearings in the 719 . . E (VEB) 1) and 70 . . E (VEX) series provide high reliability and
(VEX) series . Compared to high-speed B superior accuracy for applications such as
design bearings, high-speed E design bear- high-speed machining centres, milling
ings have a higher speed capability and they machines, internal grinding machines,
can accommodate heavier loads . This desir- and woodworking machines .
able combination makes bearings in the
719 . . E (VEB) and 70 . . E (VEX) series an
excellent choice for demanding applications .
1) Where applicable, designations in parentheses and
italics refer to the corresponding SNFA equivalent .
3
The assortment
High-speed, E design
The new, super-precision bearings in the Bearings in both series are manufactured to
719 . . E (VEB) and 70 . . E (VEX) series are two tolerance classes and are available with bearings
available in an extended range as follows: three contact angles, two ball materials and
two ring materials . Those suitable for uni- Super-precision single row angular contact
• Open bearings in the 719 . . E (VEB) series versal matching or mounting in sets are ball bearings in the 719 . . E (VEB) and
accommodate shaft diameters ranging produced to various preload classes, to meet 70 . . E (VEX) series are designed for very
from 8 to 120 mm; sealed bearings from almost all application requirements in terms high operational speeds .
20 to 120 mm . of speed and rigidity . Matched bearing sets
• Open bearings in the 70 . . E (VEX) series with a special preload can be supplied on
accommodate shaft diameters ranging request . Bearing variants for direct oil lubri-
from 6 to 120 mm; sealed bearings from cation are available .
10 to 120 mm . Bearings in the 719 . . E (VEB) and 70 . . E
(VEX) series, like all angular contact ball
bearings, are nearly always adjusted against
a second bearing to balance the counter-
forces . To accommodate heavier loads and
axial loads in both directions, the bearings
are used in sets consisting typically of up to
four bearings .
Features and benefits of SKF super-precision angular contact ball bea rings: High-speed, E design
Features Benefits
• Open osculation • Very high speed capability
• High number of relatively large balls • Relatively high load carrying capacity, high degree of rigidity
• P4A or PA9A tolerance classes • Superior running accuracy, short running-in time
• Optimized chamfer design • Facilitated mounting
• ISO 19 and ISO 10 dimension series • Compact cross sections
• Optimized phenolic resin cage • Improved behaviour at high speeds
• High-nitrogen stainless steel rings (NitroMax variant) • Extended bearing service life, superior corrosion resistance
• Non-contact seals (sealed variant) • Prevent entry of contaminants, high-speed capability
• Ready-to-mount (sealed variant) • Reduced mounting time
• Relubrication-free (sealed variant) • Reduced maintenance
• Lubrication features (direct oil lubrication variants) • Optimized oil lubrication
• Asymmetrical inner and outer rings • Accommodate radial loads and axial loads in one direction,
good permeability for lubrication
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Features of E design bearings include:
A
• asymmetrical inner and outer rings
a°
• a high number of relatively large balls
• an optimized lightweight cage with opti-
mized guiding clearance
• an optimized chamfer design
• an open osculation r ,r
1 3
The asymmetrical bearing rings enable the
b°
bearings to accommodate radial loads and r ,r
2 4
axial loads in one direction . The bearings
have a high number of relatively large balls
for increased load carrying capacity . The
bearings have an outer ring shoulder-
E design bearings accommodate very high Optimized design of the bearing ring chamfers
guided cage made of fabric reinforced phe-
speeds and relatively high loads. facilitates mounting.
nolic resin, designed to enable good lubri-
cant supply to the ball/raceway contact
areas . The guiding clearance between the
cage and the outer ring is optimized for
improved behaviour at high speeds .
Depending on the series and size, the shape
of some of the chamfers on the inner and
outer rings is optimized for improved
mounting accuracy . As a result, mounting is
not only facilitated, but there is also less risk
of damage to associated components . The
open osculation of E design bearings ena-
bles very high speed capability .
Open bearings in the 70 . . E (VEX) series
with a bore diameter d ≥ 10 mm typically
719 E (VEB) 719 B (HB) 70 E (VEX) 70 B (HX)
have seal grooves in the outer rings .
High-speed E design bearings can accommodate higher speeds and heavier loads, compared to
high-speed B design bearings.
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Bearing series Contact angles Ball materials
Standard bearings are manufactured with Standard bearings are available with:
The assortment of super-precision bearings the following contact angles:
presented in this brochure includes two ISO • steel balls, no designation suffix
dimension series: • a 15° contact angle, designation suffix CE (1) • ceramic (bearing grade silicon nitride)
• a 25° contact angle, designation suffix balls, designation suffix HC (/NS)
• the extremely light 19 series ACE (3)
• the light 10 series As ceramic balls are considerably lighter and
Bearings with an 18° contact angle, desig- harder than steel balls, hybrid bearings can
Bearings in both these series are suitable nation suffix FE (2), are available on request . provide a higher degree of rigidity and run
for very high operational speeds and where With three contact angles to choose from, considerably faster than comparably sized
there is tight radial mounting space . designers can optimize their application all-steel bearings . The lower weight of the
based on axial load, speed and rigidity ceramic balls reduces the centrifugal forces
requirements . A larger contact angle pro- within the bearing and generates less heat .
Bearing variants
vides a higher degree of axial stiffness and a Lower centrifugal forces are particularly
higher axial load carrying capacity . However, important in machine tool applications
Based on the operating conditions in preci- this reduces speed capability . where there are frequent rapid starts and
sion applications, bearing requirements can stops . Less heat generated by the bearing
vary . As a result, there are many variants of means less energy consumption and longer
SKF super-precision angular contact ball bearing and grease service life .
bearings in the 719 . . E (VEB) and 70 . . E
(VEX) series to choose from .
Series comparison
When increased system rigidity is required, bear-
ings in the 719 series accommodate a lar7g2er shaft
70
diameter for a7 g1iv9en outside diameter, compared Three contact angles accommodate different The bearings are available in an all-steel and
to b7e1ar8ings in the 70 series. axial load, speed and rigidity requirements. hybrid variant.
718 719 70 72 15° 18° 25°
Steel balls Ceramic balls
6
Sealed bearings Bearings made from Open bearings for direct oil
NitroMax steel lubrication
Bearings in most sizes can be supplied with A
an integral seal fitted on both sides and filled
with premium grease . The seal forms an Bearings in the 719 . . E (VEB) and 70 . . E To accommodate direct oil lubrication, the
extremely narrow gap with the cylindrical (VEX) series can be supplied with rings outer ring of open bearings can be manu-
surface of the inner ring shoulder . made from NitroMax steel . NitroMax is a factured with two lubrication holes . Add-
When compared to bearing arrangements new generation high-nitrogen stainless steel itional features are available, depending on
with open bearings and external seals, those with superior corrosion resistance, the bearing series and size .
with sealed bearings provide a number of enhanced fatigue strength and a high
advantages including: degree of impact toughness . This ultra-
Single bearings and
clean steel can extend bearing service life in
• extended bearing service life applications under good (full-film) as well as matched bearing sets
• reduced need for maintenance critical (thin-film) lubrication conditions .
• reduced inventory Standard bearings made from NitroMax Bearings in 719 . . E (VEB) and 70 . . E (VEX)
• reduced risk of lubricant contamination steel are supplied with ceramic balls . The series are available, standard, as:
during mounting and operation combined properties of the NitroMax steel
rings and ceramic balls greatly improve • single bearings
Sealed bearings are identified by the desig- bearing performance, enabling these bear- • single, universally matchable bearings
nation prefix S (suffix /S) . ings to run several times longer than con- • matched bearing sets
ventional hybrid bearings . • sets of universally matchable bearings
Sealed hybrid bearings made from Nitro-
Max steel are identified by the designation
prefix SV (suffix /S/XN) .
S719 E S70 E
(VEB /S) (VEX /S)
Most sizes are
available in a
sealed variant

Bearing variants for direct oil lubrication
Description Bearing variant
for open bearings in the series
719 . . E (VEB) 70 . . E (VEX)

Designation suffix H (H) H1 (H1) L (GH) H (H) H1 (H1) L (GH) L1 (G1)
Bore diameter range 8 to 35 40 to 120 20 to 120 6 to 171) 20 to 120 20 to 120 20 to 120
d [mm]
Lubrication features Two lubrication holes in the Annular groove and two lubri- Two lubrication holes in the Annular groove and two lubri-
outer ring cation holes in the outer ring outer ring cation holes in the outer ring
Sealing features None Two annular grooves in the None Two annular grooves in the
outer ring fitted with O-rings outer ring fitted with O-rings
1) Bearings in the 70 . . E (VEX) series with a bore diameter d = 6 to 9 mm do not have seal grooves in the outer ring, as shown in the illustration above .
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Applications
Machine tool applications, such as high- In the highly contaminated environment Where maximum speeds are required,
speed milling machines, machining centres of a machine tool spindle, one of the pri- bearing variants for direct oil lubrication
and grinding machines, require high pos- mary causes of premature bearing failure is combined with ceramic balls provide opti-
itioning accuracy and low levels of heat gen- the ingress of solid contaminants and/or mum performance .
eration . The ability of bearings in the cutting fluid into the bearing cavity . To elim-
719 . . E (VEB) and 70 . . E (VEX) series to inate this problem, sealed bearingsin the
meet these requirements and still provide a S719 . . E (VEB .. /S) and S70 . . E (VEX .. /S)
high degree of rigidity at very high oper- series are an excellent solution .
ational speeds, makes them an excellent
solution for these and similar applications .
Applications Requirements Solution
• High-speed machining centres • High-speed capability
(horizontal and vertical) • High positioning accuracy
• High-speed milling machines • High degree of system rigidity
• High-speed internal grinding • Low energy consumption
machines • Long service life
• High-speed spindles for PCB drilling • Facilitated mounting
• Turbomolecular pumps • Increased machine uptime
• Woodworking machines • High power density for compact
designs
• Effective sealing against
contaminants
SKF super-precision angular contact ball
bearings in the 719 .. E (VEB) and 70 .. E (VEX)
series
8
A
9
Bearing arrangement design
Single, universally matchable Matched bearing sets
Bearing arrangements using SKF super-
bearings
precision angular contact ball bearings in Bearings can be supplied as a complete
the 719 . . E (VEB) and 70 . . E (VEX) series bearing set consisting of two, three or four
can be designed using single bearings or Universally matchable bearings are specif- bearings . The bearings are matched to each
bearing sets . An example of the ordering ically manufactured so that when mounted other during production so that when
possibilities for a three-bearing arrange- in random order, but immediately adjacent mounted immediately adjacent to each other,
ment is provided in table 1 . to each other, a given preload and/or even in a specified order, a given preload and/or
load distribution is obtained without the use even load distribution is obtained without
of shims or similar devices . These bearings the use of shims or similar devices . The bore
Single bearings
can be mounted in random order for any and outside diameters of these bearings are
desired bearing arrangement . matched to within a maximum of one-third
Bearings in the 719 . . E (VEB) and 70 . . E Single, universally matchable bearings of the applicable permitted diameter toler-
(VEX) series are available as single (stand- are available in three preload classes and ance, resulting in an even better load distri-
alone) bearings or single, universally match- are identified by the designation suffix G (U) . bution when mounted, compared to single,
able bearings . When ordering single bear- universally matchable bearings .
ings, indicate the number of individual Matched bearing sets are available in
Bearing sets
bearings required . three preload classes for symmetrical bear-
ing arrangements and six preload classes for
Bearings in the 719 . . E (VEB) and 70 . . E asymmetrical bearing arrangements .
Single bearings
(VEX) series are available as matched bear-
Single bearings are intended for arrange- ing sets or as sets of universally matchable
Sets of universally matchable
ments where only one bearing is used in bearings . When ordering bearing sets, indi-
bearings
each bearing position . cate the number of bearing sets required
Although the widths of the bearing rings (the number of individual bearings per set is
are made to very tight tolerances, these specified in the designation) . The bearings in these sets can be mounted
bearings are not suitable for mounting in random order for any desired bearing
immediately adjacent to each other . arrangement . The bore and outside diam-
eters of universally matchable bearings in a
set are matched to within a maximum of
Table 1
Example of the ordering possibilities for a three-bearing arrangement
Design criteria What to order Bearing designation1) Order example
Bearing arrangement is not known Three single, universally matchable bearings 70 . . EG . ./P4A 3 x 7014 CEGA/P4A
(VEX .. 7CE .. U..) (3 x VEX 70 7CE1 UL)
Bearing arrangement is not known and A set of three universally matchable bearings 70 . . E/P4ATG . . 1 x 7014 CE/P4ATGA
improved load distribution is desirable (VEX .. 7CE .. TU..) (1 x VEX 70 7CE1 TUL)
Bearing arrangement is known and Three bearings in a matched set 70 . . E/P4AT . . 1 x 7014 CE/P4ATBTA
maximum rigidity is required (VEX .. 7CE .. T..) (1 x VEX 70 7CE1 TD17,5DaN)
Bearing arrangement is known and Three bearings in a matched set 70 . . E/P4AT . . 1 x 7014 CE/P4ATBTL
maximum speed is required (VEX .. 7CE .. T..) (1 x VEX 70 7CE1 TDL)
1) For additional information about designations, refer to table 17 on pages 32 and 33 .
10