Interpump SS71 - Definition of Static Pull to Apply on Belts

ENGLISH
30
Dimensions (in mm)
Belt section as per DIN symbol
DIN 7753 part 1 and B.S. 3790 symbol B.S./ISO
Belt section as per DIN symbol
DIN 2215 and B.S. 3790 symbol B.S./ISO
XPB/SPB
SPB
17
B
XPC/SPC
SPC
22
C
Pitch width b
w
14.0 19.0
Increased grooving width b
1
≈
α = 34° 18.9 26.3
α = 38° 19.5 27.3
c 8.0 12.0
Distance between grooving and 23 ± 0.4 31 ± 0.5
f 14.5 ± 0.8 20.0 ± 1.0
Increased grooving depth t
min
22.5 31.5
α 34° by primitive diameter d
w
from 140 to 190 from 224 to 315
38°
narrow-section V-belts
DIN 7753 part 1
> 190 > 315
α 34° by primitive diameter d
w
from 112 to 190 from 180 to 315
38°
classic section V-belts
DIN 2215
> 190 > 315
Tolerance for α = 34°-38° ± 1° ± 30’
Pulleys for b2 by grooving number z
b2 = (z-1) e + 2 f
1 29 40
2 52 71
3 75 102
4 98 133
5 121 164
6 144 195
7 167 226
8 190 257
9 213 288
10 236 319
11 259 350
12 282 381
Minimum pulley diameter must be respected.
Do not use laminated V-belts. Fig.10
b) Use high performance belts – for example XPB instead of
SPB – as a lower quantity of belts for the same transmitted
power may be necessary and a consequent shorter
resulting distance compared to the shaft shoulder (P.T.O)
“a” of Fig.11.
Shaft shoulder
(P.T.O.)
Fig.11
c) Pull the belts according to manufacturer instructions.
Excessive pulling can cause reduced bearing life and wear
out the pulley prematurely. Pulling depends on dierent
variables as indicated in par.9.12.
d) Belt length has a natural tolerance ≥ ± 0.75%. For this
reason, the 4 belts must be purchased as a pair.
e) Follow the direction of the belt pull as shown in Fig.11 for
other needs, contact our Technical or Customer Service
Departments.
f) Take care of the alignment of the driving pulley and driven
pulley grooves.
9.12 Denition of static pull to apply on belts
Static pull depends on:
a) The wheelbase between the two pulleys (belt length).
b) The load due to static pull of the belt.
c) The number of belts.
d) The winding angle of the smallest pulley.
e) Average speed.
f) Etc.
Values of the static pull to be applied can be obtained from
the diagram in Fig.12 for belts with a XPB prole in relation to
the wheelbase.