FHA-C Series - Harmonic Drive LLC

Chapter 2 Guidelines for sizing• Calculating average loads: average radialand axial loads, average output speedWhen the radial and/or axial loads vary during motion, calculate and verifythe life of the cross roller bearing converting the loads to their average values.• Average radial load: Frav10/3n 1 t 1| Fr 1| 10/3 +n 2 t 2| Fr 2| 10/3 ...n n t n| Frn10/3Faav= (2)√ n 1 t 1 + n 2 t 2 + ... +nn tnNote: "Fr 1 " is the maximum radial load in "t 1 " range,and "Fr 3 " is the maximum radial load in "t 3 " range.– Axial load +Fr 1Fr 2Fr 3Fa 1Fa 2Time• Average axial load: Faav10/3n 1 t 1| Fa 1| 10/3 +n 2 t 2| Fa 2| 10/3 ...n n t n| Fa n| 10/3√Faav= (3)n 1 t 1 + n 2 t 2 + ... +n n t n– Axial load +Fa 3TimeNote: "Fa 1 " is the maximum radial load in "t 1 " range,and "Fa 3 " is the maximum radial load in "t 3 " range.t 1 t 2 t 3• Average output speed: Nav10/3n 1 t 1 +n 2 t 2 +...n n t n (4)Nav=t 1 + t 2 + ... + t n– Axial load +n 1n 2n 3Time• Calculating radial load factor and axial load factorBoth load factors are different with average loads as follows:• When the right formula is satisfied,X=1.0, and Y=0.45FaavFrav + 2(Frav ( L r+ R ) + Faav.La ) /dp1.5 (5’)Where, the variables of the formula are:Mmax: Maximum torsional moment in N•m(kgf•m); obtained by the formula (1)Frmax: Maximum radial load in N(kgf); See Fig.1.Famax: Maximum axial load in N(kgf); See Fig.1.Lr, La: Loading point in mm; See Fig.1.R: Offset; See Fig.1 and Table 1.dp: Circular pitch of roller: See Fig.1 and Table 1.21