Software optimizes transmission component efficiency to improve vehicle mileage

    As environmental standards tighten and consumers demand higher fuel efficiency, automakers need to develop lighter components to help achieve low vehicle emissions and high mileage. Voith Turbo, a subsidiary of German company Voith, focuses on developing hydraulic transmission and braking systems for automobiles and rail trains. It believes that one of the ways to achieve the above goals is to enhance the efficiency of the gearbox.

    Voith considers material lightweighting as the most important way to improve transmission efficiency. Although engineers have optimized the transmission design as much as possible during the development phase, they believe there is still room for efficiency improvement. In order to optimize the structure of automatic transmission components, Voith uses FE-DESIGN's Tosca Structure software for optimization.

    Tosca Structure is a modular software system for non-parametric structural optimization. Voith Turbo used it to optimize the planetary carrier assembly in the gearbox. A planetary gear system consists of one or more outer planetary gears that rotate around an inner sun gear. The system itself also rotates around the sun gear.

    From left to right: the original design of the planetary gear carrier, computer-aided engineering design, software design, and lightweight design after structural simplification

    First, engineers used Tosca Structure software to map out the functional areas and component connection areas, and the remaining space was defined as the "available design space". After first ensuring the functionality and manufacturability of the components, they were optimized. With this approach, the functional stiffness on the planet carrier (referring to the durability of the bearings and the equal load on each planet gear side) was guaranteed.

    Tosca Structure then automatically defines the excess force flux area and simulates the removal of this part of the material in the computer. Since the various production process standards have been set directly in the software, the casting parameters can be directly modified when optimizing using the CAD system.

    “With Tosca Structure, we found the best way to save material and increase the efficiency of the planetary gear train in our automatic transmissions,” says Bernd Wӧhrle, Head of Commercial Vehicle Technology at Voith Turbo.

    The newly designed planet carrier assembly is 30% lighter than the previous generation. The more compact planet carrier structure means that more components can be accommodated in the gearbox mold, which means that more castings can be produced with the same casting process.