The advantage that air-spring cab suspension has over conventional steel-spring suspension is that of a low natural frequency, which greatly enhances a commercial vehicle’s riding comfort. So-called sleeve air springs are the type normally used in truck and tractor cab suspension. Depending on space availability and the design of add-ons, they can be set up directly with the vibration damper as a one-piece spring strut or alternatively installed in parallel arrangement to the dampers.
As a rule air springs used for cab suspension are arranged as four-corner suspension between the driver’s cab and the chassis frame. In addition to improving comfort, air-spring cab suspension offers the advantage that a manufacturer can use a uniform component regardless of customer variant and equipment preferences. The air spring equalizes any force differences as may occur because of differences in cabin weight (raised roof, air-conditioning system etc.) or driving speed. It does this by means of a control valve that automatically varies the internal pressure in such a way that the driver’s cab is statically always in the manufacturer’s specified design position vis-à-vis the vehicle chassis.
