Abstract:  In order to solve the problems of poor adaptability,  easy tipping,  and low trafficability performance of existing hilly tractors,  the 504type hilly tractor with an automatic leveling mechanism was designed. The hilly tractor adopted mechanical drive,  a fourwheeldrive walking system,  independent steering systems on both sides,  and a parallel fourbar automatic leveling mechanism,  which could realize the tractor posture automatic profile leveling. Threedimensional modeling of the tractor was carried out based on SolidWorks. ADAMS software was used to model the virtual prototype and analyze the dynamic simulation of roll stability. The results showed that: the leveling action range of the automatic leveling mechanism was 732 mm,  which can ensure the horizontal level of the vehicle body on the slope of 25°. The limit tilt angle of uphill and downhill were both 45°. The longitudinal slip angle of uphill and downhill was 33.69° and 16°,  respectively. The obstacleclimbing height of its front and rear driving wheels was 214 mm. The maximum roll angle of the vehicle body in the leveled state was 37.5°,  which was close to the theoretical calculation of 35.93°. Both the front and rear drive axles of the 504type hilly tractor could be leveled independently and always keep the tractor body in a horizontal position,  which could meet the requirements of hilly and mountain production.

Key words: hilly tractor, profiling and leveling mechanism, stability, obstaclesurmounting performance

摘要： 针对丘陵山地拖拉机坡地适应性差，易翻倾，通过性差等问题，设计一种具有自动调平机构的504型丘陵山地拖拉机。整机采用机械传动，四驱轮式行走系统，两侧独立传动转向系统，平行四杆自动调平机构，可实现拖拉机姿态自动仿形调平。基于SolidWorks对拖拉机进行整机三维建模，运用ADAMS软件对虚拟样机进行侧倾稳定性动态仿真分析。结果表明: 自动调平机构调平动作范围732 mm，可在25°的坡地上保证车身横向水平。上坡极限翻倾角及下坡极限翻倾角均为45°，上坡纵向滑移角为33.69°，下坡纵向滑移角为16°，前后驱动轮越障高度为214 mm。调平状态下车身的最大侧倾角为37.5°，与理论计算35.93°非常接近。该机前后驱动桥均可进行独立调平，保证机身始终处于水平姿态，能够满足丘陵山地生产作业要求。

关键词: 丘陵山地拖拉机, 仿形调平机构, 稳定性, 越障性能