Harmonic Planetary Gears

Compact precision for the highest demands

For applications requiring high accuracy but with a gear ratio of less than 45:1, we have developed compact and precise Harmonic Planetary Gears. These compact gearboxes are manufactured to the same high quality standard as the proven Harmonic Drive® gears.

Harmonic Planetary Gears consist of a number of gear wheels arranged around a central gear. Since this arrangement is reminiscent of planets orbiting the sun, the central wheel is also referred to as the sun gear, while the surrounding ones are called planet gears. They are located within an external gear ring. The sun gear is driven by a motor and transmits its motion to the surrounding planet gears, which roll against the surrounding gear ring and thus orbit the sun gear evenly.

 

Requirements of the market for gears that support high speeds or low ratios often require the highest precision. Harmonic Planetary Gears meet this requirement. Due to their integrated motor connection with clamping element and motor flange, they allow easy mounting of servo motors. The special design with a flexible ring gear in the last stage ensures consistently high precision over the entire service life - we call this Permanent Precision®.

Harmonic Planetary Gears

Planetary gears are characterised by their high level of efficiency; they also display a high power density in comparison to other types of gears, due to their compact construction. The use of the external ring gear in particular reduces both the volume and mass of this type of gear.

It also enables high torque transmission in a small construction space thanks to the use of multiple parallel tooth combinations with several orbiting wheels. As the torque is distributed over several gear wheels, the tooth forces are smaller than in other types of gear.

Moreover, no synchronisation is necessary, which means that it is possible to change gear without interrupting the traction. As all gear wheels constantly mesh with each other, the planetary gear operates at a low noise level.

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Harmonic Drive® Planetary Gears | Harmonic Drive SE

How it works

Due to the special design with an elastic ring gear in the last stage, our planetary gears guarantee a constant high precision over the entire lifetime - Permanent Precision®!

Learn more about Harmonic Planetary Gears in the video.

Features of Harmonic Planetary Gears

No increase in play


A large number of practical tests and applications have confirmed that there is no increase in play over the entire lifetime.

Backlash less than 1 minute of arc
 

By using a thin walled hollow ring gear in the output stage, backlash of less than 1 minute of arc is achieved. This special design means we can guarantee constant throughout the lifetime without any additional increase in backlash, we call this Permanent Precision.

Repeatability of less than 20 arc seconds


High precision manufactured components and the flexible ring gear as compensation mechanism are the basis for excellent repeatability within ± 20 seconds of arc.

High capacity output bearing


Due to the very compact and high capacity cross roller bearing, our planetary gear units have a very high tilting rigidity and excellent smooth running characteristics at the output flange.

Ratios between 3:1 and 45:1
 

The selection of standard gear ratios permits economical gear production resulting in an attractive price to performance ratio.