Atlanta, GA (USA), Friedrichshafen (Germany). ZF's automatic commercial vehicle transmission TraXon excels with its numerous technical advantages. The complete system as well as its individual components are designed for sustainability. For example, the clutch system is also consistent with the trend toward diesel engines with lower operating speeds. Besides that, the clutches feature low wear and thus facilitate economic commercial vehicle maintenance. The ConAct pneumatic release cylinder that is available in the TraXon transmission as standard also contributes to that, enabling finally metered maneuvering.
Clutches are exposed to the effective drive forces in a particularly direct manner. This basic rule also applies to an automated commercial vehicle transmission such as the ZF TraXon, where the engaging and disengaging processes are performed electromechanically or pneumatically, i.e. independently of the driver, and are therefore very short and precise. ZF has also revised the range of available dry clutches for the TraXon automatic transmission system.
In this context, new torsional dampers which meet the requirements of the trend toward higher engine torques in combination with lower operating speeds are used. While fuel consumption can be cut by reducing the operating speed in highway traffic, the vibration load at the interface between engine and transmission increases at the same time. ZF will use new torsional dampers with lower stiffness for its dry clutches, enabling compensation for the significantly higher stress on the torsional dampers during operation with high torques and reduced speed. Thanks to the very robust design, this goal could be achieved without having to increase the number of torsion springs in the clutch disk. This would have led to worse NVH (noise, vibration, harshness) characteristics of the complete driveline.
In an automated transmission system for commercial vehicles, the control electronics are in charge of the engaging and disengaging processes as well as the gear changes. These are then performed by mainly pneumatic actuators. With the ConAct pneumatic clutch cylinder, ZF is using an especially powerful actuator for clutch actuation. The concentric design and its coaxial arrangement in relation to the transmission input shaft offer advantages regarding installation length and weight and at the same time reduce the number of system components required. The ConAct release cylinder shows significant advantages also with regard to its functions when it comes to clutch service life and sensitiveness of the clutch control mechanism compared to the systems previously used in automated transmissions.