Perhaps the most apparent is to increase precision, which really is a function of manufacturing and assembly tolerances, gear tooth surface finish, and the guts distance of the tooth mesh. Sound is also suffering from gear and housing materials in addition to lubricants. In general, be prepared to spend more for quieter, smoother gears.
Don’t make the error of over-specifying the motor. Remember, the input pinion on the planetary must be able manage the motor’s result torque. What’s more, if you’re utilizing a multi-stage gearhead, the result stage must be strong enough to soak up the developed torque. Obviously, using a more powerful motor than required will require a bigger and more expensive gearhead.
Consider current limiting to safely impose limits on gearbox size. With servomotors, output torque can be a linear function of current. Therefore besides protecting the gearbox, current limiting also shields the electric motor and drive by clipping peak torque, which may be from 2.5 to 3.5 times continuous torque.
In each planetary stage, five gears are concurrently in mesh. Although you can’t really totally get rid of noise from this assembly, there are several methods to reduce it.
As an ancillary benefit, the geometry of planetaries fits the shape of electric motors. Thus the gearhead could be close in diameter to the servomotor, with the result shaft in-line.
Highly rigid (servo grade) gearheads are generally more costly than lighter duty types. However, for speedy acceleration and deceleration, a servo-grade gearhead may be the only sensible choice. In this kind of applications, the gearhead could be seen as a mechanical spring. The torsional deflection caused by the spring action adds to backlash, compounding the consequences of free shaft motion.
Servo-grade gearheads incorporate a number of construction features to reduce torsional stress and deflection. Among the more prevalent are large diameter result shafts and beefed up support for satellite-gear shafts. Stiff or “rigid” gearheads have a tendency to be the costliest of planetaries.
The kind of bearings supporting the output shaft depends on the load. High radial or axial loads generally necessitate rolling low backlash gearbox component bearings. Small planetaries can often manage with low-cost sleeve bearings or various other economical types with fairly low axial and radial load capability. For larger and servo-grade gearheads, heavy duty result shaft bearings are often required.
Like the majority of gears, planetaries make noise. And the quicker they operate, the louder they get.
Low-backlash planetary gears are also obtainable in lower ratios. While some types of gears are usually limited by about 50:1 or more, planetary gearheads expand from 3:1 (single stage) to 175:1 or more, depending on the amount of stages.