low backlash planetary gearbox

Perhaps the most obvious is to increase precision, which is a function of manufacturing and assembly tolerances, gear tooth surface finish, and the guts distance of the tooth mesh. Sound is also affected by gear and housing components as well as lubricants. In general, expect to pay out more for quieter, smoother gears.
Don’t make the mistake of over-specifying the engine. Remember, the insight pinion on the planetary should be able deal with the motor’s output torque. What’s more, if you’re using a multi-stage gearhead, the result stage must be strong enough to absorb the developed torque. Certainly, using a low backlash planetary gearbox better motor than required will require a larger and more expensive gearhead.
Consider current limiting to safely impose limits on gearbox size. With servomotors, output torque is certainly a linear function of current. So besides protecting the gearbox, current limiting also defends the engine 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 eliminate noise from such an assembly, there are many ways to reduce it.

As an ancillary benefit, the geometry of planetaries fits the shape of electric motors. Therefore the gearhead could be close in diameter to the servomotor, with the output shaft in-line.
Highly rigid (servo grade) gearheads are usually more expensive than lighter duty types. However, for fast acceleration and deceleration, a servo-grade gearhead may be the only sensible choice. In such applications, the gearhead could be seen as a mechanical spring. The torsional deflection resulting from the spring action increases backlash, compounding the effects 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 output 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 strain. High radial or axial loads usually necessitate rolling component bearings. Small planetaries can often get by with low-price sleeve bearings or various other economical types with fairly low axial and radial load ability. For larger and servo-grade gearheads, heavy duty output shaft bearings are usually required.
Like most gears, planetaries make sound. And the faster they operate, the louder they get.

Low-backlash planetary gears are also obtainable in lower ratios. Although some types of gears are usually limited by about 50:1 and up, planetary gearheads extend from 3:1 (solitary stage) to 175:1 or even more, depending on the number of stages.

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