- 6 -
Planetary gearboxes RG
Gearbox selection
Gearbox selection is made according to the following formulas for Continuous or Intermittent operation.
S1 - Continuous operation
for
S
p
> 60% or S
t
> 20 min
where:
T
2 nom
[Nm]
= Gearbox nominal torque
T
1 nom
[Nm]
= Motor nominal torque
T
2 ISO
[Nm]
= Gearbox nominal torque according to ISO
n
2 nom
[rpm]
= Output nominal speed
n
2 eqv
[rpm]
= Output average speed
S5 - Intermittent operation
for
S
p
< 60% or S
t
< 20 min
where:
T
2 acc
[Nm] = Gearbox max. acceleration
torque
T
1 acc
[Nm] = Motor max. acceleration
torque
i
[...]
= Reduction ratio
f
s
[...]
= Shock factor (see graph)
[...]
= Gearbox efficiency
Z
h
[1/h] = Cycle number per hour
T
2eqv
[Nm] = Equivalent torque, resultant by
individual torques of duty cycle
T
2max
[Nm] = Max. torque
n
2eqv
[rpm] = Cycle equivalent speed
n
2n
[rpm] = Cycle speed
n
2mid
[Nm] = Average speed
t
n
[ s ]
= Cycle times
t
1
...t
4
[ s ] = Acceleration, operation, deceleration, pause times
Shock factor
Shock factor is a service factor that keeps into account rapid motion inversions associated with quick acceleration times.
Such overloads must be considered when sizing.
f
s
-
Shock factor
Z
h
-
Cycle numbers per hour
Gearbox selection
t
t
t
n
t
n
n
n
t
n
t
t
n
T
t
n
T
T
t
t
t
t
3600
Z
f
i
T
T
n
1
n
1
n
2
1
1
2
eqv
2
3
midn
2
n
1
mid
2
1
n
1
midn
2
3
n
max
2
1
1
mid
2
3
1
max
2
eqv
2
4
3
2
1
h
s
acc
1
acc
2
nom
2
eqv
2
ISO
2
nom
2
nom
1
nom
2
n
n
T
T
65
.
0
i
T
T