Harmonic Drive FHA Mini Series, Manual

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Chapter 2 Guidelines for sizing
FHA-mini
27
• Equivalent dynamic radial load
The equivalent dynamic radial load is:
(6)
Where, the variables of the formula are:
Fr av : Average radial load in N(kgf); obtained by formula (2).
Fa av : Average axial load in N(kgf); obtained by formula (3).
dp: Circular pitch of roller: See Fig.1 and Table 1.
X: Radial load factor; obtained by formula (5)
Y: Axial load factor; obtained by formula (5')
Lr, La: Loading point in mm; See Fig.1.
R: Offset; See Fig.1 and Table 1.
•
Life of cross roller bearing
Calculate the life of cross roller bearing with the formula below:
(7)
Where, the variables of the formula are:
L
B-10
: Life of cross roller bearing in hour
N av : Average output speed in rpm; obtained by formula (4).
C: Basic dynamic load rating in N (kgf). See Table 1.
Pc: equivalent dynamic radial load in N (kgf); obtained by formula (6).
fw: Load factor:
For smooth operation without shock or vibration: fw=1 to 1.2
For normal operation: fw=1.2 to 1.5
For operation with shock and/or vibration: fw=1.5 to 3
• Life of cross roller bearing for swaying motion
Calculate the life of cross roller bearing with the formula below:
(8)
Where, the variables of the formula are:
Loc: Life of cross roller bearing in hour
n
1
: Number of reciprocating oscillation per minute.
C: Basic dynamic load rating in N (kgf). See Table 1.
Pc: Equivalent dynamic radial load in N (kgf); obtained by
formula (6).
fw: Load factor:
For smooth operation without shock or vibration: fw=1 to 1.2
For normal operation:
fw=1.2 to 1.5
For operation with shock and/or vibration: fw=1.5 to 3
0: Half of sway angle; See the right figure.
If the sway angle is less than 5 degrees, please contact us.
Sway motion
Sway angle
θ
10/3
6
Pc fw
C
60
10
Loc







 

=

90
1
n