The continuing growth of the US trucking industry has led and will continue to lead to a shortage of truck drivers and qualified mechanics. Therefore a high priority at the fleets is driver retention and reduction in maintenance.
In addition emission regulations lead to challenges in the area of drive-train vibrations induced by the new engines implemented in recent years and in the years to come to comply with the emission regulations.
High operating costs to periodically inspect and manually adjust clutches used in combination with unsynchronized transmissions, can be avoided if the clutch facing- and iron-wear could be compensated for automatically.
Using the patented ZF Sachs XTend™ self-adjust and Controlled Center Plate Technology the basis was given to develop a reliable self-adjusting clutch with consistent, “drag-free” clutch operation to lower the operating costs and to provide a clutch that is easy to operate by the driver.
This paper describes the development process of the Twin XTend Clutch (see Figure 1) starting with the studying of the market demands, the -from the demands derived- design targets, the features of the Twin XTend meeting the targets and the rig- and field testing methods validating the full functionality of the self-adjusting clutch over product life.