Double-planetary speed modulation gearbox

TANDLER description: Double-planetary speed modulation gearbox PD2 | PDS

Double-planetary speed modulation gearbox

PD 2 gearboxes are strong, coaxial speed modulation gearboxes. PDS gearboxes are suitable for treble the speed and can transmit a third of the torque of a PD2 gearbox of the same size.

PD2 and PDS gearboxes have identical external dimensions and the same size can be interchanged in accordance with the performance.

The PD2 is a double planetary gear with internal gear ratios of i1=1:3 and i2=3:1, whereby the rotational speed is modulated on one of the two ring gears. The second ring gear is fixed.

The PDS (S stands for “schnell”, meaning fast) is externally identical to the PD2, and it also has the same function. The input or output is implemented via the sun gears rather than via the planetary carrier gears. The advantage of the PDS is therefore obvious: Because of the internal gear ratios of i1 = 3: 1 and i2 = 1: 3, three-fold increased speeds can be transmitted. The downside, however, is that with the same gearbox size the nominal torque drops to one third. The use of 6 planetary gears for each gearbox stage, instead of the standard 3 planetary gears, provides compensation by increasing the transmissible torque.

Technical data

Ratios of shaft d1
i = n1:n2 = 1:1 i = n1:n2 = 1:1
Ratios of shaft d3
i = n3:n1 = n3:n2 = 135:1 i = n3:n1 = n3:n2 = 45:1
Gearbox sizes
7 7
Max. torque
2500 Nm 830 Nm (Reinforcement on request)
Max. speed at shaft d1
1000 min-1 3000 min-1
Max. speed at shaft d3
3000 min-1 3000 min-1
Input and output
Coaxial Coaxial

Using multi-start worm gears, the speed modulation ratio may be reduced.