Harmonic Drive LLC | 42 Dunham Ridge, Beverly, MA 01915 | 800-921-3332
Harmonic Drive and Harmonic Planetary are registered trademarks of Harmonic Drive LLC.


Planetary Gear Principle

Planetary gears have simultaneous meshing between the sun gear and planet gears and between the planet gears and the internal gear. The sun gear is connected to the motor and a carrier, supporting the planet gears, is connected to the output. Single stage planetary gears can achieve reduction ratios up to 10:1. Ratios above 10:1 utilize a two stage design where the carrier of the first stage drives the sun gear of the second planetary stage.  

Video demonstrating how our HPGP Harmonic Planetary gears work. 



Operating Diagram 


First Stage

Rotation of the input pinion transfers revolution motion to the first-stage planet gears that mesh with it. The motion is then transferred to the first-stage carrier through the planetary shaft to the second-stage pinion.

The direction of rotation of the first stage carrier is the same as the input pinion.

Second Stage

The second-stage pinion gear is driven by the first-stage carrier and provides the input to the second-stage planet gears. Similar to the first-stage, the rotation is then transferred to the second-stage carrier. The second stage carrier serves as the output of the gearhead.

The direction of rotation of the second stage carrier is the same as the input pinon.

Click on the links to learn more about the HPN Series and the HPG / HPGP Series Harmonic Planetary gearheads


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