公开(公告)号：EP0982170A4

公开(公告)日：2002-10-24

申请号：EP98919592

申请日：1998-05-13

申请人： YANMAR AGRICULT EQUIP ,  SEIREI IND

发明人： OHYA TERUMITSU ,  SHIMADA TAKANOBU

IPC分类号： B60K17/10 ,  B62D11/10 ,  B62D55/06

CPC分类号： B62D11/10 ,  B60K17/105 ,  Y10T74/19149

摘要： A drive unit provided with a power transmission path interlockingly connecting an engine (E) to left and right sprockets (12L, 12R), which are adapted to drive left and right crawlers (11) of left and right traveling parts (1L, 1R), via a non-stage traveling transmission (21) and an auxiliary traveling transmission unit (28) capable of changing the speed of a working vehicle in a plurality of stages. The power transmission path is provided with a non-stage steering transmission (20), left and right steering transmission units (48L, 48R) and left and right planetary gears (40L, 40R) all of which are adapted to be operated for speed change in accordance with a turning operation of a steering wheel (7). This construction enables a pivot turn and a spin turn of a working vehicle body to be made, the swinging performance of the working vehicle to be improved, the maneuvering of the vehicle to be done easily, and the construction of the drive unit to be simplified. It also becomes possible for the vehicle body to travel in a speed range which cannot be covered by the non-stage traveling transmission alone, and reduce the fuel consumption by lowering an output rotational frequency of the non-stage traveling transmission during a high-speed travel of the vehicle on a road.