Perhaps the most obvious is to improve low backlash planetary gearbox precision, which really is a function of manufacturing and assembly tolerances, gear tooth surface finish, and the center distance of the tooth mesh. Sound can be affected by gear and housing components as well as lubricants. In general, be prepared to pay more for quieter, smoother gears.
Don’t make the mistake of over-specifying the motor. Remember, the insight pinion on the planetary must be able deal with the motor’s output torque. Also, if you’re utilizing a multi-stage gearhead, the result stage should be strong enough to absorb the developed torque. Certainly, using a better motor than required will require a bigger and more costly gearhead.
Consider current limiting to safely impose limits on gearbox size. With servomotors, result torque is certainly a linear function of current. So besides safeguarding the gearbox, current limiting also defends the 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 it’s impossible to totally get rid of noise from such an assembly, there are many ways to reduce it.
As an ancillary benefit, the geometry of planetaries fits the form of electric motors. Hence the gearhead can be close in diameter to the servomotor, with the result shaft in-line.
Highly rigid (servo grade) gearheads are usually more costly than lighter duty types. However, for rapid acceleration and deceleration, a servo-grade gearhead may be the only wise choice. In such applications, the gearhead could be seen as a mechanical spring. The torsional deflection caused by the spring action increases backlash, compounding the effects of free shaft motion.
Servo-grade gearheads incorporate many construction features to minimize torsional stress and deflection. Among the more common 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 type of bearings supporting the output shaft depends upon the strain. High radial or axial loads usually necessitate rolling component bearings. Small planetaries can often manage with low-price sleeve bearings or additional economical types with fairly low axial and radial load capability. For bigger and servo-grade gearheads, heavy duty output shaft bearings are often required.
Like most gears, planetaries make sound. And the faster they run, the louder they obtain.
Low-backlash planetary gears are also available in lower ratios. Although some types of gears are generally limited by about 50:1 and up, planetary gearheads expand from 3:1 (one stage) to 175:1 or even more, depending on the amount of stages.