SEM images of 20MnCr5 powder for L-PBF.
SEM images of 20MnCr5 powder for L-PBF.

Porsche Engineering is making use of a PM product to make components for the company’s e-drive powertrains.

The company is investigating how to implement GKN Powder Metallurgy 20MnCr5 low carbon alloy steel to redesign the differential housing with the ring gear, the part with the largest weight reduction potential.

In conventional transmissions, the ring gear and the differential housing serve different functions within the transmission. The ring gear is made of specific steel, which is then hardened and grinded for preciseness. The differential housing is normally cast and used for torque transfer from the ring gear to the center bolt and bevel gears. 

Due to the manufacturing processes and assembly methods, the wide ring gear teeth are supported by a thin and sometimes off-centered disc. The disc is connected to the differential housing. Using computer aided design (CAD) and topology structural optimization, a new shape based on the forces was designed and the maximum available space within the transmission was then defined.

According to GKN, the improvement weight reduction and stiffer shape of the gears led to a more efficient transmission, with a 13% weight reduction, 43% decrease of tooth stiffness variations in radial direction, 69% decrease of tooth stiffness variations in tangential direction and 8% reduction of inertia.

This story uses material from GKN, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.