2-3 Verifying and examining load weights
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付
S
e
le
c
tion gui
de
lin
e
s
Maximum load moment load
The formula below shows how to calculate the maximum load
moment load (M
max
).
Verify that the maximum load moment load (M
max
) is less than
or equal to the allowable load (Mc).
Verifying life
Calculating average loads (average radial and axial loads, average output rotational speed)
When the radial and/or axial loads vary during motion, calculate and verify the life of the cross roller
bearing converting the loads to their average values.
◆
Formula (1): Maximum load moment load
1000
La
max
Fa
R)
(Lr
max
Fr
max
M
⋅
+
+
⋅
=
Symbols used in the formula
M
max
Maximum load moment load
Nm
Fr
max
Max. radial load
N
Refer to Fig.1.
Fa
max
Max. axial load
N
Refer to Fig.1.
Lr ,La
――――
mm
Refer to Fig.1.
R
Offset amount
mm
Refer to Fig.1 and Table 1.
◆
Formula (2): Average radial load (Frav)
n
n
10/3
n
n
n
10/3
10/3
10/3
t
n
t
n
t
n
Fr
t
n
Fr
t
n
Fr
t
n
Fr
2
2
1
1
2
2
2
1
1
1
+
+
+
+
=
av
The maximum radial load in section t
1
is given by Fr
1
,
while the maximum radial load in section t
3
is given by
Fr
3
.
◆
Formula (3): Average axial load (Faav)
n
n
10/3
n
n
n
10/3
10/3
10/3
t
n
t
n
t
n
Fa
t
n
Fa
t
n
Fa
t
n
Fa
2
2
1
1
2
2
2
1
1
1
+
+
+
+
=
av
The maximum axial load in section t
1
is given by Fa
1
,
while the maximum axial load in section t
3
is given by
Fa
3
.
◆
Formula (4): Average output rotational speed
(Nav)
n
n
n
t
t
t
t
n
t
n
t
n
N
2
1
2
2
1
1
+
+
+
+
+
+
=
av
Time
+
R
adi
al
load
-
Fr
1
Fr
2
Fr
3
Time
+
A
x
ial
load
-
Fa
1
Fa
2
Fa
3
Time
+
O
ut
put
r
ot
at
ional
s
peed
-
n
1
n
2
n
3
t
1
t
2
t
3
Fig. 2: Illustration of load variation
Fr
Fa
La
Lr
R
Load
dp
Fig. 1: External load action
Actuator
