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1. Technical defi nitions<br />
1.1 Service factor<br />
fS = service factor:<br />
takes into account the gravity of the application; it depends on the:<br />
working conditions and type,<br />
type of operation,<br />
start-up frequency.<br />
fs • T2 < Tcont<br />
Service factor<br />
Type of load fs<br />
Uniform U Moderate M Heavy H<br />
Number of start- ups per hour 50 50 50<br />
Hydraulic motors 1,0 1,0 1,2 1,0 1,2 1,4 1,2 1,4 1,6<br />
Electric motors 1,1 1,2 1,4 1,2 1,4 1,6 1,4 1,6 1,8<br />
1.2 Reduction ratio<br />
ie = effective reduction ratio:<br />
ratio between the input and output velocity of the gearbox;<br />
ie = n1/n2 .<br />
1.3 Correction factor kf<br />
kf = output support lifetime correction factor:<br />
used to obtain the theoretic duration of the support for values of n2 h different from those found in the<br />
catalogue. For all gearboxes the external load curves are calculated for:<br />
- n2 h = 100.000 for the output supports<br />
- n1 h = 1.500.000 for the input supports<br />
1.4 Torque arm length<br />
Lmin= minimum advised torque arm length for shaft mounted applications.<br />
1.5 Shrink disk torque<br />
1.6 Speed<br />
Mtmax= maximum torque transmittable by the shrink disk when supplied by <strong>Jahns</strong>.<br />
Transmittable torque by the gearbox and the shrink disk must always be checked for compatibility.<br />
n1 = input velocity<br />
is the input velocity of the gearbox.<br />
n2max = maximum output velocity<br />
maximum output velocity of the gearbox for continuous operation; values of velocity near the maximum<br />
can be achieved in compatibility with the work cycle; for further information please contact thetechnical<br />
services.<br />
1.7 Lifetime<br />
n2 • h = output duration index:<br />
product of the output velocity and the duration in hours.It represents a number proportional to the<br />
stress applied to the element which limits the life of the gearbox. To correlate the velocity and the<br />
duration, the torque Tcont is expressed as a function of the product n2 • h.<br />
With the speed n2 and the torque Tcont required, the duration in hours can be calculated;or alternatively, if<br />
the speed and the duration in hours required are known then the Tcont that the gearbox can transmit<br />
can be calculated:<br />
H Y D R A U L I K<br />
Page B. 6<br />
www.jahns-<strong>hydraulik</strong>.de