Optibelt ZRP - ZRL-V Drive Design

37
Driver and driven units
Driven unit: horizontal accumulating conveyor
system, two parallel timing belts on
steel support rails
Mass moved: three loaded wooden pallets total weight
each 62.5 kg
Required
conveying speed:
v = 1.0 m/s
Prime mover: three-phase AC motor
Starting torque: M
A
= 0.7 M
N
Driver speed: n
1
= 145 min
-1
Operating conditions, layout
Daily operating time: max. 8 hours
Starts/stops per day: 2
Type of start: under load
Type of load: medium shock
Ambient conditions: room temperature, no special
contamination
Length of conveyor: a = 2478 mm
Overall width: b
1
, B ≤ 90 mm
Clearance diameter: ≤ 150 mm
4.4 ZRL-V drive design
Drive design of optibelt ZRL-V joined endless timing belt for conveyor systems,
z
emax
= 6, v
≤≤
≤≤
≤ 2 m/s
Formulae Example
Timing belt load
c
2
= 1.6 + 0 + 0 = 1.6
c
0
= 1.6
c
6
= 0
c
8
= 0 few switching cycles
S
Bn3
= 1.6 · 735.75 = 1177 N
S
n3
= = 735.75 N
Friction due to acceleration can be neglected here
S
n3tot
= 0 + 0 + 1471.5 = 1471.5 N
S
n3tot
= 187.5 · 0 + 187.5 · 9.81· sin 0° + 0.8 · 187.5 · 9.81 · cos 0°
m
tot
= 3 · 62.5 kg = 187.5 kg
a
1
is insignificant, as m
1
is taken into account
a
1
= 0 g = 9.81
For special belt constructions, see pages 9 to 11
µ
tot
= 0.35 + 0.45 = 0.8
Sliding friction µ
1
= µ = 0.35 for PAR/wood
Sliding friction µ
2
= µ = 0.45 for PAZ/steel
α = 0°, horizontal conveyor
M
Bth
= 1.6 · 48.45 = 77.5 Nm M
Abth
= = 48.45 Nm
d
w1th
= = 131.7 mm
Calculation using circumferential force S
Bn3
S
Bn3
= c
2
· S
n3
S
n3
=
Force due to acceleration F
B
, force due to weight G and friction force F
R
S
n3tot
= F
B
+ G · sin α + F
R
· cos α
S
n3tot
= m
tot
· a
1
+ m
tot
· g · sin α + µ
tot
· m
tot
· g · cos α
Total mass m
tot
m
tot
= m
1
+ m
2
+ . . . + m
n
Acceleration a
1
and g
a
1
= g = acceleration due to gravity
Coefficient of friction m
µ
tot
= µ
1
+ µ
2
µ, µ
0
see Table 1.6, page 10
Sliding friction and frictional grip, µ
1
for belt/conveyed material
Sliding friction and frictional grip, µ
2
for belt/support rail or
guide
Angular deviation a from the horizontal
α = 0°, vertical movement, sin 0° = 0, cos 0° = 1
α = 90°, horizontal movement, sin 90° = 1, cos 90° = 0
Alternative: calculation using torque
Theoretical design torque M
Bth
M
Bth
= c
2
· M
Abth
M
Abth
=
If M
Ab
is not known: M
B
= c
2
· M
An
formulae see page 13
Theoretical pitch diameter d
w1th
d
w1th
=
1471.5
2
S
n3tot
number of belts
v
2
· 10
3
2 · s
19100 · v
n
1
S
n3
· d
wth
2000
19100 · 1.0
145
Overall drive service factor c
2
c
2
= c
0
+ c
6
+ c
8
Basic drive service factor c
0
Table 2.1, page 12
Pulley and idler correction factor c
6
Table 2.2, page 13
Start/stop factor c
8
Table 2.2, page 13
m
s
2
735.75 · 131.7
2000