IAA Commercial Vehicles: Driving Comfort is an Evergreen

by Thomas Engel, Global Account Management Commercial Vehicle at Vibracoustic

In September, the commercial vehicle sector looks to Hanover for the IAA Commercial Vehicles, the world's leading trade fair for transport, logistics and mobility. This year's trade fair will focus on future issues and trends such as automation and the connectivity, safety, environmental protection, e-mobility and new concepts for logistics and transport in the city of the future.

In addition to these trends, comfort for the driver and the durability of the vehicles also play a decisive role in the industry. The annual mileage of a truck in long-distance traffic is up to 150,000 kilometers. A truck driver therefore sits at the wheel about ten times longer on average than a driver of a passenger car – particularly difficult road conditions such as damage or unevenness have a negative effect on the driver's health and thus on driving safety. Modern vibration control technology can make an important contribution here and ensure maximum comfort by comfortably supporting and absorbing the driver cab.
The possibilities for implementation here are manifold and range from chassis mounts to air springs and cab mounts. Air springs, for example, help to compensate for load fluctuations in the vehicle: Commercial vehicles are equipped with a complex spring system because the rear axles in particular are exposed to strong load fluctuations. When operating without a trailer, the axles only have to carry the tractor's own weight. In a fully loaded semitrailer truck, on the other hand, the two rear axles are subjected to loads of more than ten tons each. Air springs are the optimum combination of safety, comfort and cost efficiency, especially on the rear axles. Thanks to the constant height of the tractor unit and trailer, the driving characteristics are good under any load condition. Moreover, the spring system cannot break through – chassis and load are spared. The principle is similar to that of a passenger car: pressure on the piston compresses the enclosed air volume. When the piston is relieved again, the pressure drops. Adaptive dampers can be used to further optimize driving behavior.

The pressure-tight connection to the other components of the air spring is realized via tension beads located at the ends of the bellows. In the form of cabin air springs – they are used in the driver cab suspension – they serve to comfortably support the driver cab. They have a low, uniform natural frequency and keep the vehicle at a constant level. This significantly reduces vibrations caused by a wide variety of road surfaces or load fluctuations, which are transmitted to the driver cab via the chassis. Cab air springs offer a perfect balance between driving comfort and dynamics. In addition, the increased comfort for the driver supports the safe driving of the vehicle.

Cab mounts also make a significant contribution to increased driving comfort: they dampen annoying vibrations and noises and thus provide good working conditions for the driver. The suspension varies from vehicle to vehicle and is usually provided by bushings, air springs or steel springs – they are often used in combination. Since a driver cab weighs between 600 and 1,900 kilograms, depending on its design, the demands placed on the cab mounts are very high. The developers at Vibracoustic therefore calculate the elastomers and metal parts of the components using modern finite element methods. To save valuable development time for vehicle manufacturers, the mounts are then tested on the test bench. The result of this work is long-life cab mounts that meet high demands in terms of comfort and functionality.