Page 513 - Rollingbearings

Permissible speed
Temperature Permissible speed

limits
The speed ratings in the product tables
indicate:
The permissible operating temperature for
cylindrical roller bearings can be limited by: • the reference speed, which enables a
quick assessment of the speed capabilities
• the dimensional stability of the bearing from a thermal frame of reference
rings and rollers • the limiting speed, which is a mechanical
• the cage limit that should not be exceeded unless
• the seals the bearing design and the application are
• the lubricant adapted for higher speeds

Where temperatures outside the permissible For additional information, refer to Operating
range are expected, contact SKF. temperature and speed, page 130
SKF recommends oil lubrication for bear-
Bearing rings and rollers ings with a ring centred cage When these
bearings are grease lubricated, the nd
m
SKF cylindrical roller bearings are heat sta- value is limited:
bilized up to 150 °C (300 °F)
• for bearings with an LA, LB, LL, MA, MB,
Cages ML, MP, JA, JB or MH cage
† nd ≤ 250 000 mm/min 6
m
Steel, brass, light alloy or PEEK cages can be • for bearings with a PA or PHA cage
used at the same operating temperatures as † nd ≤ 450 000 mm/min
m
the bearing rings and rollers For tempera-
ture limits of cages made of other polymer where
materials, refer to Polymer cages, page 188 d = bearing mean diameter [mm]
m
Page 511 footnot = 0,5 (d + D) Table 7
Seals n = rotational speed [r/min] Conversion factors for limiting speeds of
single row cylindrical roller bearings
The permissible operating temperature for For single row bearings with a standard
Bearing with
PUR seals is –20 to +80 °C (–5 to +175 °F) cage, the values for the limiting speed are standard cage alternative standard
Typically, temperature peaks are at the listed in the product tables Conversion fac- cage
seal lip tors to estimate the limiting speed for bear- P, PH, J, PA, PHA, ML
ings with an alternative standard cage are M, MR MA, MB
Lubricants listed in table 7
P, PH, J, M, MR 1 1,3 1,5
Temperature limits for greases used in PA, PHA, MA, MB 0,75 1 1,2
sealed double row full complement cylin-
ML 0,65 0,85 1
drical roller bearings are provided in table 1,
page 503 For temperature limits of other
SKF greases, refer to Selecting a suitable
SKF grease, page 116
When using lubricants not supplied by Table 6
SKF, temperature limits should be evaluated Lubrication factors for cylindrical roller bearings
according to the SKF trafic light concept
(page 117) Bearing types Lubrication factors
Oil lubrication Grease
lubrication
k 1 k 2 k 1 k 2

Single row and high-capacity bearings 1,5 0,15 1 0,1
Single row full complement bearings 1 0,3 0,5 0,15
Double row full complement bearings 0,35 0,1 0,2 0,06

511