<div class="htmlview paragraph">Hydrostatic drives are winning ever-greater preference in fast-moving construction machines vith speeds approaching 40 km/h and a high proportion of reverse-gear operation. A very important precondition to achieving optimum, effective technical solutions is the cooperation of engine, hydrostatic system, multi-ratio powershift transmissions and axles as a complete drive system. The function and complexity of open and closed-loop control systems are also of major influence.</div> <div class="htmlview paragraph">Operation of the vehicle must be made simpler for the driver while improving driving comfort, and the speed with which the drive system responds to the drivers commands must be increased. For this to be achieved, the way in which drive power is utilized under constantly changing operational conditions must involve a high degree of automated functions in addition to the manual commands.</div> <div class="htmlview paragraph">To meet these demands a new design concept for 2-speed powershift transmissions has been developed with the 2 HL 100 and 2 HL 110, for applications primarily in wheel excavators from 10 to 22 metric tons service weight and in wheel loaders up to 12 metric tons. Design considerations essentially concentrated on the following requirements:</div> <div class="htmlview paragraph"> <ul class="list disc"> <li class="list-item"> <div class="htmlview paragraph">Powershift transmissions</div> </li> <li class="list-item"><div class="htmlview paragraph">Using the powershift clutches as auxiliary and parking brakes, thus obviating the need for a separate multi-disc safety brake</div> </li> <li class="list-item"><div class="htmlview paragraph">Higher power-to-weight ratio and improved technology</div> </li> <li class="list-item"><div class="htmlview paragraph">Rating and design as a standard transmission for use in open and closed hydraulic circuits</div> </li> <li class="list-item"><div class="htmlview paragraph">Improved efficiency</div> </li> <li class="list-item"><div class="htmlview paragraph">Improved driving comfort and shift quality</div> </li> <li class="list-item"><div class="htmlview paragraph">Independent lubrication of the transmission</div> </li> <li class="list-item"><div class="htmlview paragraph">Hydraulic or electrical overspeed protection for the hydraulic motor</div> </li> <li class="list-item"><div class="htmlview paragraph">Reducing transmission noise</div> </li> <li class="list-item"><div class="htmlview paragraph">Standard control block containing the shift and brake valves for the transmission</div> </li> <li class="list-item"><div class="htmlview paragraph">Useable with single and dual circuit braking systems</div> </li> </ul> </div>