Control
Shaft ratio:
The differential action or speed trimming is
achieved by rotating the control shaft(s). It
is important to note that there are four control
shaft ratios to choose from for each HDD size;
81:1, 101:1, 121:1 and 161:1. These ratios define
the relationship between the control shaft and
the output. For instance, with an 81:1 ratio,
an operator would have to rotate the control shaft
81 times to turn the output one full revolution
ahead of, or behind, the primary input.
Control Shaft Direction of rotation:
Rotating the control shaft in the same direction
as the input will cause the output to advance
or move ahead of the input. Rotating the control
shaft in the opposite direction as the input will
cause the output to retard.
Control shaft running/holding torque:
Because of the inherent high efficiency of the
Harmonic Drive gear components, the HDD control
shaft may backdrive. Therefore, it is necessary
to apply a holding torque to the control shaft
to maintain a 1:1 transmission ratio. Control
shaft holding/running torques may be calculated
using the following formula:
Tcm = T ÷ (Cr x 0.5)
Control Motor Torque= Tcm
System Torque= T
Control Shaft Ratio= Cr
|
