Axis Gear Ratios
Referring again to Figure 6-1, the transmission of axes 1 through 4 consists of
two stages: the timing belt drive, and the Harmonic Drive.
The overall gear ratio of the output shaft which moves the axis is therefore
expressed as:
N
T
× N
HD
= N
AXIS
Where:
N
T
is the belt drive ratio (that is, the radii ratio):
Pulley
B
Pulley
A
N
HD
is the Harmonic drive ratio, as described above.
N
AXIS
is the overall gear ratio of the axis.
SCORBOT-ER IX Gear Ratios
N
T
N
HD
N
AXIS
Axis 1
1.33 : 1 161 : 1 214.13 : 1
Axis 2
1.52 : 1 160 : 1 243.8 : 1
Axis 3
1.33 : 1 160 : 1 213.33 : 1
Axis 4
1.8 : 1 100 : 1 180 : 1
Axis 5
100 : 1 100 : 1
Thus, one rotation (360°) of axis 3, for example, requires 213.33 rotations of the
motor shaft. The actual movement of the axis, however, is limited by the arm’s
mechanical structure.
User’s Manual 6 - 7 SCORBOT-ER IX
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