Harmonic Drive FHA Mini Series, Manual

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Chapter 2 Guidelines for sizing
FHA-mini
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• Equivalent static radial load
Equivalent static radial is obtained by formula (9) below.
(9)
Where, the variables of the formula are:
Po: Equivalent static radial load in N (kgf);
M max : Maximum torsional moment in N•m(kgf•m); obtained by the formula (1)
Fr max : Maximum radial load in N(kgf); See Fig.1.
Fa max : Maximum axial load in N(kgf); See Fig.1.
dp: Circular pitch of roller: See Fig.1 and Table 1.
• Static safety factor
Generally, the static safety factor is limited by the basic static load rating (Co). However, for the heavy
duty, the factor is limited by the following formula:
(10)
Where, the variables of the formula are:
fs: Static safety factor. See Table 4.
For precise positioning operation:
fs ≥ 3
For operation with shock and/or vibration: fs ≥ 2
For normal operation:
fs ≥ 1.5
Co: Basic static load rating in N (kgf). See Table 1.
Po: Equivalent static radial load in N (kgf); obtained by formula (9).
Po
Co
fs
=