Browsing by Subject "Fahrzeugantrieb"

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Untersuchungen zur Bewertung stufenloser Fahrantriebe für Mähdrescher
(2011) Bernhard, Björn; Kutzbach, Heinz Dieter
Due to changes in the general ecologic and economic conditions for European agriculture, the discussions on agricultural engineering have taken the efficiency and the performance of drive concepts into account, recently. At this, focus is laid on the wheel drive since this is the main drive for tractors and even in self-propelled harvesting machines it requires a large amount of the power of the combustion engine. Because of its specific characteristics like reversibility and continuously variable adjustment, the wheel drive of the combine harvester and its continuously variable torque converter have special requirements on drive technology. Therefore, the torque converter is investigated in this thesis which is aimed at analysing different, continuously variable torque converters for wheel drives of combine harvesters to detect basics for their evaluation. After examining the theoretical foundations of continuously variable torque converters a hydrostatic and an electric torque converter are chosen for further testing. The hydrostatic torque converter mainly consists of a variable displacement pump, an electronic control unit and a variable displacement motor, while the electric torque converter is assembled from a generator and an electric motor which are controlled via the power electronics of inverters. After design and parallel setup of the torque converters, both of them are mounted to the same combine harvester. Afterwards comparative tests are carried out with this combine. To get a wide basis for the evaluation of the torque converters, the different operating conditions which occur within the operation of a combine harvester were covered by the use of four separate operating ranges. These are: ? Standby (operation of the torque converter at 0 speed to determine the standby power) ? Field work (operation of the torque converter at partial load during harvest) ? On-road drive (operation of the torque converter at partial load during transfer) ? Full load (operation of the torque converter at heavy drawbar pull)