The concept of a double differential has enormous potential for electric and hybrid vehicles as well as a host of other applications.

The second differential is built around the first centre unit, both units having to same axes around which they rotate at different speeds. Due to the load sharing of the two opposite planets, the torque of each gear is only 50% compared to a conventional bevel gear mesh.

The efficiency of the double differential compares to multiple stage cylindrical gear transmission comprising the same ratio. The compact nature of the double differential offers additional efficiency compared to these other transmission options.

Double differentials are a new type of transmission with proven ability to reduce the input rpm into lower rpms in a relatively compact unit.

Not only can they have applications in ev and hybrid transmissions but also helicopters, wind turbines, agricultural equipment and many other sector uses.

The article from Gear Technology magazine by Dr.Hermann Stadtfeld and Dr.Haris Ligata introduces us to the double differential and illustrates how it works and its potential.