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Product data Page ................4 Calculation examples Page ..............57
Example 2 Example 3
The attachment of a shock absorberof an off-highway vehicle The 320-bar
industrial hydraulic cylinder of a fully
automatic press for building
industry waste Given:Radial load (constant direction):
Operation Load, F Given:Radial load: F
r = 7 kNAxial load: F
a = 0,7 kNHalf angle of oscillation: âž” Table , page 21 ),and with P = F page 76 β = 8°( , the basicdynamic load rating C = 31,5 kNand
the sphere diameter d
r Time caseperiod, t
I300 kN10 %
II180 kN40 %
III120 kN50 %The number of press cycles n = 30 perhour, and the movement between the
end positions (90°) is made in 10 sec-
onds. The operating temperature is
less than +50 °C.Required:A maintenance-free spherical
plain bearing with the sliding contact sur-
face combination steel/PTFE fabric for
a rating life of 5 years for 70 h of oper-
ation per week.Using a guideline value for the loadratio C/P = 2( fig
3 , page 16 )Frequency of oscillation: f = 15 min
–1 Load frequency: 2–5 Hz
Maximum operating temperature: +75 °CRequired:A bearing which will have a basic rat-
ing life corresponding to a driven dis-
tance of 100 000 km at an average
speed of 65 km/h without maintenance.For design reasons, spherical plainbearing GE 20 C with the sliding con-
tact surface combination steel/sinter
bronze composite is proposed. From
the bearing table, b
1 = 0,2 (from Table
6 , page 26, fora load frequency over 0,5 Hz and
25 < p < 40 N/mm
2 )b
2 = 1 (from Diagram
16 , page 26, for temperatures < 80 °C)the basic rating lifefor bearing GE 20 Cwith the sliding contact surface com-
bination steel/sinter bronze composite
is1 400G
k = 29 mm.First the equivalent dynamic bearingload must be determinedF
h =b
1 b
2 ––––––p
1,3 3 v1 400=0,2
rI the required basicdynamic load ratingC = 2P = 2
a /F
r = 0,7/7= 0,1which gives factor y = 1,4 from × 1 × ––––––––––– 31
1,3 × 0,002≈1 600 hThis basic rating lifecorresponds to adistance (at an average speed of
65km/h) of 1 600 × 300= 600kNFrom the product table, Diagram
2 , page 19 . The equivalentdynamic bearing load is thusP =yF page 78 , bear-ing GE 60 TXE-2LShas a basic dy-
namic load rating C = 695 kNand a
sphere diameter d × 65 = 104 000 km.
r =1,4 × 7=9,8 kNA first check of bearing size using the
k = d
m = 80mm ischosen( âž” page 21 ).First it is necessary to check that theoperation cases I to III fall within the
permissible range of the pv diagram pv diagram
7 Table , page 22 , page 21 , shows thatthe values for the specific bearing load
(K = 100 from )P9,8p = K –– = 100 , page 23 .The sliding velocity is the same forall three cases. The angle of oscillation
is specified as 2 β , the time t as thetime taken to pass through 2
4 8 β in sec-onds. Complete cycle duration is 4 × ––––– = 31 N/mm β ( âž” pages 16 and 21 ).2
2 C31,5and the sliding velocity (d v=8,73 × 10 β
m = d
k = 29 mm)v= 5,82 × 10
–7 d
–6 m β f= 5,82 × d
m –––t90=8,73 × 10
–7 × 29 × 8 × 15 =0,002 m/sso that this lies in the permissible oper-ating range I of the pv diagram. Using × 10
–6 × 80 × ––– 10= 0,0063m/s 32