Gear Synthesis

The term “gear synthesis” in the field of gear-wheel drives, usually refers to the systematic identification of the structures. Here, a specific gear structure is characterised by the type and number of gear-wheel stages as well as the gear-wheel connections via fixed shafts.

It is always possible to meet specific gear requirements by means of numerous different gear structures representing the solution space.  
Regarding vehicle gears, the solution space can amount to a size, even for a small number of gears (e.g. two-speed electric drive systems), that makes the time- and cost-efficient analysis of the solution space and, thus, finding the most favourable solution for the requirement impossible.

Therefore, MAHLE ZG Transmissions GmbH have been applying the “PlanGear” gear synthesis programme since 2010. The “PlanGear” program is a 100 % in-house-development by ZG and is being continuously enhanced. The program is based entirely on an algorithm which we developed. This algorithm enables a very efficient structure search for most different types of gear, such as:

  • Non-power shift gears (e.g. manual gear-boxes)
  • Power shift gears with one power-shifting element only
  • Automatic power shift gears (e.g. torque-converter gear-box)
  • Dual clutch gear-box
  • Combinations, such as those with dual clutch and automatic gear-boxes

All gear structures can consist of designs of planetary gears, such as Ravigneaux or Wolfrom planetary gear sets. They can also contain spur gear stages arranged on any number of wave-trains.

Since those hybrid gear-boxes, mostly driven by combustion engines or electric machines, are of great interest in the vehicles sector, “Plan Gear” has been equipped with manifold functions enabling the finding and assessing of such gear structures. One example of this is the so-called DHT (“Dedicated Hybrid Transmission”) gear-boxes that can be created for a wide range of requirements without much effort.