BASF develops lightweight top mount

BASF is now expanding its expertise in top mounts to enable car manufacturers an optimum combination of weight savings, pleasant acoustics and vibration damping. The unique NVH (noise, vibration, harshness) solution is made possible by combining two of BASF's plastic specialties: the micro-cellular polyurethane elastomer Cellasto and the highly glass-fibre reinforced polyamide Ultramid A3WG10 CR. The top mount with the Cellasto element and the Ultramid housing is around 25 percent lighter than conventional aluminum die-cast versions with rubber. It was developed and optimised for serial production using BASF's simulation tool Ultrasim.

"By joining Cellasto with an Ultramid housing in a top mount for the first time, we are combining our Verbund expertise in the best materials, customised design and meticulous quality management to provide our customers with rapid component development and implementation, shorter process chains and global use," says Wolfgang Micklitz, head of the global business management Cellasto. "This new and complex component offers a sustainable innovation that contributes to further CO₂ savings along with high safety and maximum comfort."

The top mount links the shock absorber to the chassis and thus has a decisive influence on driving comfort and dynamics. The interplay between the materials of the individual components is therefore of crucial importance: Cellasto shows very good static and dynamic behaviour, has a long life usage and takes up only a small amount of installation space. Components made of Cellasto have been used in cars for more than 50 years. The PA66 grade Ultramid A3WG10 CR is reinforced with 50 percent glass fibres and is therefore exceptionally rigid and solid, even at high temperatures. The engineering plastic is particularly suitable for dynamic loads and thus generally a good alternative to metal.

Combined to form the top mount, the actual bearing, the jounce bumper and the dust tube for the shock absorber can be functionally integrated and achieve good damping and acoustics. With a manufacturing technique especially developed by BASF, housing and bearing are joined to each other permanently. The CAE tool Ultrasim was used to calculate the load situations relevant for top mounts, the lifespan and the injection-molding process, taking into account the reaction forces of the Cellasto core.

Under the Cellasto brand name, BASF develops, produces and distributes components made from micro-cellular polyurethane elastomers for parts in chassis, powertrain and interior such as spring aids, top mounts, spring isolators and transmission mounts.