Two Stage Roller Chain Drive
get the most compact transmission designs try using all-geared
reduction stages. These are trickier to build because of the
control that needs to be maintained over shaft separation and
parallelism but can provide fairly large speed reductions.
The image shows a two stage
straight spur gear drive transmission with a 250W electric
wheelchair motor. With, for example, two 8:1 spur gear
reduction stages the arrangement would give a total speed ratio
of 64:1 in a fairly compact space - good for some low speed high
drive torque applications.
The straight spur gearing can
also be driven from the output shaft so will not lock-up if the
power is removed from drive motor, this allows the road wheel to
drive the motor as a generator for regenerative braking