Wire Ropes Under Bending and Tensile Stresses - Wire Ropes: Tension, Endurance, Reliability - page 313

DS bear
d 2

¼ 0 : 024 d

D S d 2 :

ð 3 : 100 Þ

For rarely used sheaves with slide bearings, the friction coefficient is much
greater. The sliding bearings in ( 3.99 ) can be set to l bear = 0.1 with an additional
charge of 50 % for tearing loose.
The rope force loss for two seals of roller bearings is

¼ 2 p q d axle
D d 2

DS seal
d 2

: ð 3 : 101 Þ

For the seals of roller bearings, the friction resistance is q = 0.01 N/mm
according to the SKF catalogue. Then again with d axle = 5d, the specific rope
force loss for two seals of roller bearings is

DS seal
d 2

¼ 1 : 6
D

in N/mm 2 : ð 3 : 102 Þ

Müller ( 1990 ) found a specific friction force between q = 0.07 and 0.20 N/mm
for standard sliding lip seals with spring pressing.

3.5.1.1 Simplified Calculation

A simplified calculation of the rope force loss is possible with ( 3.97 ) if the con-
stants c 0 and c 1 have been supplemented to take into account the resistance caused
by the roller bearings and the sliding seals of roller bearings.
To take the roller bearing resistance into account, the rope force loss is set the
same as in ( 3.97 ) with c 0 = 0 and ( 3.100 )

1 : 33

D
d

S

d 2 ¼ 0 : 024 d D S

c 1bear

d 2 :

Then the constant for the influence of the sheave bearing is

0 : 33

D
d

c 1bear ¼ 0 : 024

0 : 075 : ð 3 : 103 Þ

To take the seals of roller bearings into account, the rope force loss is set the
same as in ( 3.97 ) with c 1 = 0 and ( 3.102 )

1 : 33

¼ 1 : 6
d

D
d

d

c 0seal

D :