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1019659 11/2014
4.3.1 Efficiency Calculations
4.3 Efficiency Versus Load
Efficiency for Harmonic Drive® gears varies depending on the output torque. The efficiency curves are for gears operating at
rated output torque. Efficiency for a gear operating at a load below the rated torque may be estimated using a compensation
curve and equation as shown on the next page.
Calculation Procedure
Example
Efficiency of HFUC-20-80-2A-GR
with input speed n=1000 rpm
output torque T=19.6 Nm
at 20° C ambient temperature.
Lubrication: Grease
The efficiency may be determined
using the efficiency graphs.
From matching chart
η
= 78 %
Calculate
the torque factor V.
mit:
T
av
= Average torque
T
N
= Rated torque at rated speed
T
av
= 19.6 Nm
T
N
= 34.0 Nm
K depending on gear type and V,
see illustration 24.2.
Efficiency
η
L
=
η
. K
η
L
= 78 . 0.93 = 73 %
[Equation 24.2]
[Equation 24.3]
Calculating Factor K
V =
T
av
T
N
K
Table 24.1
1,0
0,8
0,6
0,2
0
0,2 0,4 0,6 0,8
V
K
0,4
1,0
V =
= 0.57
19.6 Nm
34.0 Nm
Illustration 24.4
