23
1021387 12/2018
V02
Normally, the gear life is determined by the life of the Wave Generator bearing. Depending on the specific load conditions the output bearing can also be determinant for the unit
life.
1)
F = Four-point bearing, C = Cross roller bearing
2)
See illustration 23.2
3)
These values are valid for moving gears. They are not based on the equation for lifetime calculation of the output bearing but on the maximum allowable deflection of the
Harmonic Drive® Component set. The values indicated in the table must not be exceeded even if the lifetime equation of the bearing permits higher values.
4)
These values are valid for gears at a standstill and for a static load safety factor f
s
= 1.8 for sizes 14 ... 20 and 1,5 for sizes 25 ... 58. For other values of f
s
, please refer to
chapter 4.7.
5)
These data are valid for f
w
= 1.3, n = 15 rpm and L
10
= 15000 h
3) 4) 5)
These data are only valid if the following conditions are fulfilled:
For: M, M
0
: F
a
= 0, F
r
= 0 | F
a
: M = 0; F
r
= 0 | F
r
: M = 0, F
a
= 0
6)
Average value
3.3.6 Bearings
Output Bearing
SHG Units incorporate a high stiffness cross roller bearing to support output loads. This specially developed bearing can
withstand high axial and radial forces as well as high tilting moments. The reduction gear is thus protected from external
loads, so guaranteeing a long life and constant performance. The integration of an output bearing also serves to reduce subse-
quent design and production cost, by removing the need for additional output bearings in many applications. However, in some
applications the machine element to be driven requires additional bearing support. In this case, please take care to avoid
overdetermination of the bearing arrangement. The cross roller bearing of the unit should be used as the fixed bearing,
whilst the additional support bearing should be floating, if possible. Table 23.1 lists ratings and important dimensions for the
output bearings.
Table 23.1
Symbol
[Unit]
SHG-14
SHG-17
SHG-20
SHG-25
SHG-32 SHG-40 SHG-45 SHG-50 SHG-58 SHG- 65
Bearing type
1)
C
C
C
C
C
C
C
C
C
C
Pitch circle ø
d
p
[m]
0.050
0.060
0.070
0.085
0.111
0.133
0.154
0.170
0.195
0.218
Offset
2)
R [m]
0.022
0.024
0.026
0.030
0.036
0.044
0.048
0.053
0.062
0.072
Dynamic load rating
C [N]
5800
10400
14600
21800
38200
43300
77600
81600
87400
130000
Static load rating
C
0
[N]
8600
16300
22000
35800
65400
81600
135000
149000
171000
223000
Permissible dynamic
tilting moment
3)
M [Nm]
74
124
187
258
580
849
1127
1487
2180
2740
Permissible static
tilting moment
4)
M
0
[Nm]
144
328
515
1070
2425
3623
6949
8505
11159
16200
Tilting moment
stiffness
6)
K
B
[Nm/arcmin]
25
45
73
114
291
521
748
1021
1545
2155
Permissible axial
load
5)
F
a
[N]
3050
5469
7678
11464
20088
22770
40808
42911
45961
68364
Permissible radial
load
5)
F
r
[N]
2044
3664
5144
7681
13459
15256
27341
28751
30794
45804
Illustration 23.2