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The maximum load on the belt will appear when both the preten-
sion FTv and the working load FU will act at the same time:
FTmax = FTV + FU
The maximum allowable tensile load of the belt Ftzul (see techni-
cal tables of corresponding selected belt) must be greater than
the maximum working load:
FTzul > FTmax
Calculation
Linear drives are correctly dimensioned when the total periphe-
ral force, necessary for the requested work, satisfies the 3
technical parameters of the selected belt:
- tooth shear strength
- allowable tensile load
- flexibility
The necessary data for the calculation are: the mass to be
moved, the transmission cycle, the drive layout with the related
forces, the resisting force of friction.
Friction force is generally determined by the linear bearing
manufacturer.
In case of conveying applications, it is resulting from the weight
of the conveyed goods and the coefficient of friction between sli-
der bed and belt surface. In case of accumulating conveyors the
friction between the conveyed goods and the backside of the belt
must be considered additionally.
For initial belt profile and pitch selection, use the graphs
available in the related catalogue section.
For the choice of the pulleys it is recommended to use pulleys
with the largest possible diameter.
That will reduce the belt width and optimise drive performances.
Verify of allowable tensile load
Select belts and pulleys
With:
The load (m • g • sinα ) must be considered only in vertical or
inclined drives when a mass is lifted against gravity.
Calculate total mass in motion (m)
Linear motion drives are correctly tensioned when in the slack
side a minimum tension is guaranteed in all working conditions
and for every value of FTmax (acceleration, deceleration).
It is recommended a pretension of:
FTV ≥ FU for linear drives with ELATECH® M belts
FTV ≥ 0,5 • FU for conveying applications with ELATECH® V belts
Calculate the necessary total pheripheral force F U and
torque M
Determine installation pretension FTV
Note: zemax = 12 for belts ELATECH® M
zemax = 6 for belts ELATECH® V
Determine the belt width
with FUspez depending on the rpm of the small pulley (see techni-
cal data on tooth shear strength for the selected belt type).
The diameter of the chosen pulleys, must be greater or equal to
the minimum recommended diameter for the specific belt profile
chosen (see technical data).
Verify flexibiliy
Ured Sred R c m mmmm + + + =
⎟
⎠
⎞
⎜
⎝
⎛ + ⋅ = 2
u
2
U
Ured d
d
1
2
m
m
⎟
⎠
⎞
⎜
⎝
⎛ + ⋅ = 2
a
2
S
Sred d
d
1
2
m
m
; inertia of the idler tensioning pulley
; inertia of the idler timing pulley
2000
dF
M w U ⋅
=
b U gmgmam Fμ⋅ ⋅ + ⋅ + ⋅ =
R H ab U FF FF + + =
e Uspez
0 U
z F
cF
b ⋅
⋅
=