35
1021387 12/2018
V02
4.2 Calculation of the Torsion Angle
Calculation of the torsion angle
φ
at torque T:
4.3 Accuracy of the Oldham Coupling SHG-2SO
Information concerning the Oldham coupling can be found in section 5.7.2.
In the region of tooth engagement Harmonic Drive® Gears have no backlash. If an Oldham coupling is used for the compensa-
tion of eccentricity errors of the motor shaft, a small backlash in the range of a few arcsec can occur at the output shaft, as
listed in table 35.5.
φ
= Angle [rad]
T
1
= Limit torque 1 from section 3.3.5 [Nm]
T
2
= Limit torque 2 from section 3.3.5 [Nm]
K
1
= Torsional stiffness up to the limit torque T
1
from section 3.3.5 [Nm/rad]
K
2
= Torsional stiffness up to the limit torque T
2
from section 3.3.5 [Nm/rad]
K
3
= Torsional stiffness above the limit torque T
2
from section 3.3.5 [Nm/rad]
φ
=
60 Nm - 29 Nm
11
. 10
4
Nm/rad
29 Nm
6.7
. 10
4
Nm/rad
+
φ
= 7.15 . 10
-4
rad
φ
= 2.5 arcmin
180 . 60
�
φ
[arcmin] =
φ
[rad] .
Example: HFUC-32-100-2UH
T = 60 Nm
K
1
= 6.7 . 10
4
Nm/rad
T
1
= 29 Nm
K
2
= 1.1 . 10
5
Nm/rad
T
2
= 108 Nm
K
3
= 1.2 . 10
5
Nm/rad
T T
1
T
K
1
<–
φ
=
<
φ
=
T - T
1
K
2
T
1
K
1
+
T
1
T ≤ T
2
<
T T
2
φ
=
T
2
- T
1
K
2
T
1
K
1
T - T
2
K
3
+
+
Equation 35.1
Equation 35.2
Equation 35.3
Equation 35.4
Table 35.5
Ratio
Unit
SHG-14
SHG-17
SHG-20
SHG-25
SHG-32
SHG-40
SHG-45
SHG-50
SHG-58
SHG-65
50
[arcsec]
36
20
17
17
14
14
12
—
—
—
80
[arcsec]
23
13
11
11
9
9
8
8
6
6
100
[arcsec]
18
10
9
9
7
7
6
6
5
5
120
[arcsec]
–
8
8
8
6
6
5
5
4
4
160
[arcsec]
–
–
6
6
5
5
4
4
3
3
