Optibelt ZRP - ZRM;ZRP Drive Design

26
Prime mover
Prime mover: three-phase squirrel
cage electric motor
Power: P
An
= 6.0 kW
Speed: n
1
= 1450 min
-1
Starting torque: M
A
= 2.0 M
N
Pulley clearance
diameter: as required
Drive width: b
1
, B␣ < 80 mm
Operating conditions
Daily operation: max. 16 hours
Starts/stops: approx.
150 per day
Ambient conditions: standard room
temperature, contact
with cutting oil
Drive centres: a = 410 ± 20 mm
Driven machine
Driven machine: drill
Absorbed power:P
Ab
= 5.0 kW
Driven speed: n
2
= 600 ± 10 min
-1
Start condition: no load
Type of loading: intermittent operation with
average shock loading
Pulley clearance
diameter: < 300 mm
Width: b
1
, B as required
3.4 ZRM/ZRP drive design
Drive calculation for optibelt ZRM/ZRP timing belts, Z
emax
= 12
Formulae Calculation example
Design power and belt selection
Total service factor c
2
c
2
= c
0
+ c
6
+ c
8
Basic service factor c
0
Table 2.1, page 12
Pulley and idler factor c
6
Table 2.2, page 13
Start/stop factor c
8
Table 2.2, page 13
c
2
= 1.8 + 0 + 0 = 1.8
c
0
= 1.8
c
6
= 0
c
8
= 0
Design power P
B
P
B
= P
Ab
· c
2
P
Ab
=
If P
Ab
unknown: P
B
= P
An
· c
2
Formulae page 13
Select section from graph pages 24 and 25 using small pulley
speed n
k
P
B
= 5.0 · 1.8 = 9.0 kW
Section T10 n
k
= n
1
= 1450 min
-1
Pulleys
For standard pulley ranges see pages 54 to 86,
For pulley materials and fitting see Table 5.3, page 44
T10 for standard pulleys see page 82
Number of teeth z
1
, z
2
, pitch diameter d
w1
, d
w2
and
calculation of the drive ratio i
z
1
, d
w1
see standard pulley range
z
2
= z
1
·
ii=
z
2
, d
w2
see standard pulley range
Are clearance diameters and permissible sizes acceptable?
Clearance diameter including space to fit belt > d
a
(resp. D
B
) + 2 · h
s
z
1
= 25 d
w1
= 79.58 mm see page 82
z
2
= 25 · 2.42 i = = 2.42
z
2
= 60 d
w2
= 190.98 mm see page 82
Bore: d
1
from 12 ... 30 mm d
2
from 16 ... 60 mm
Clearance diam. >189.1 + 2 · 4.5 198.1 mm < 300 mm, h
s
see p. 5
1450
600
Driven speed n
2eff
and
drive ratio i eff
n
2eff
=i
eff
=
Pitch length and drive centres with allowances
Drive centres and pulley flange arrangements
0.5 · (D
Bk
+ d
wg
) + y < a < 2 · (d
wg
+ d
wk
)
Flanges on small pulley, y
2k
see Table 5.1 page 43
0.5 · (83 + 190.98) + 10 = 147 mm 147 mm < a < 541 mm
L
wth
= 2 · 410 + · (190.98 + 79.58) +
L
wth
= 1252.6 mm
L
wSt
= 1250 mm for Section T10 see page 17
π
2
(d
wg
– d
wk
)
2
4 a
(190.98 – 79.58)
2
4 · 410
π
2
M
Ab
· n
2
9550
n
1
· z
1
z
2
n
2eff
= = 604 min
-1
i
eff
= = 2.4
z
2
z
1
n
1
n
2
60
25
1450 · 25
60
Theoretical and standard belt lengths L
wth
, L
wSt
*
L
wth
= 2 a + · (d
wg
+ d
wk
) +
L
wSt
see standard belt range, pages 16 to 19