Harmonic Drive CHA - Page 83

831018854 12/2015 V01
Torque constant (output) k
Tout
[Nm/A
rms
]
Quotient of stall torque and stall current, taking into account the transmission losses.
Torsional stiness
(Harmonic Drive® Gears) K
3
[Nm/rad]
The amount of elastic rotation at the output for a given
torque with the Wave Generator blocked. The torsional sti-
ness K
3
describes the stiness above a defined reference
torque where the stiness is almost linear.
The value given for the torsional stiness K
3
is an average
that has been determined during numerous tests. The limit
torques T
1
and T
2
and calculation example for the total tor-
sional angle can be found in sections 3 and 4 of this docu-
mentation.
Torsional stiness
(Harmonic Planetary gears) K [Nm/rad]
The amount of elastic rotation at the output for a given
torque and blocked input shaft. The torsional rigidity of the
Harmonic Planetary gear describes the rotation of the gear
above a reference torque of 15% of the rated torque. In this
area the torsional stiness is almost linear.
Transmission accuracy [arcmin]
The transmission accuracy of the gear represents the lineari-
ty error between input and output angle. The transmission
accuracy is measured for one complete output revolution
using a high resolution measurement system. The measure-
ments are carried out without direction reversal. The trans-
mission accuracy is defined as the sum of the maximum
positive and negative dierences between the theoretical
and actual output rotation angles.
Weight m [kg]
The weight specified in the catalog is the net weight with-
out packing and only applies to standard versions.
K
1
K
2
K
3
0
T
2
Torsion
φ
φ2
φ1
T
1
Torque T
K
1
, K
2
, K
3
= Torsional stiness, w = Output angle
φ1 = Torsion angle, with output torque T
1
φ2 = Torsion angle, with output torque T
2
T
N
= Rated torque
φ = Output angle
Accuracy
Transmission accuracy
360° Output
angle