一,问题的提出近年来,农村手扶拖拉机的拥有量逐年增加,其使用状况也发生了很大的变化。典型调查表明,目前手拖己有80%以上归农户使用或为农户所有。拖拉机的年工作总时数和从事运输作业的总时数均大为增加(运输作业年时数占拖拉机年工作时数的60～70%左右),而且载货时超载现象也较普遍。因而现有的以耕作为主要设计工■的驱动一牵引兼用型手扶拖拉机在结构设计上的 First, the issue put forward In recent years, the amount of rural walking tractor has increased year by year, its use has also undergone great changes. A typical survey shows that at present, over 80% of trailers have been used by farmers or owned by farmers. The total number of annual tractors and the total number of hours engaged in transport operations are greatly increased (the number of transport operations accounted for about 60 to 70% of the working hours of the tractor), and the overloading phenomenon is also common when carrying. Therefore, the existing farming as the main design workers ■ traction-driven walking tractor with a combination of structural design