丘陵山地拖拉机底盘传动及转向系统的设计

针对拖拉机在丘陵山区适应性差,田间地头转向半径大、易损害作物,耗时长和效率低等问题,设计了一种可原地转向的504型丘陵山地拖拉机底盘。整机采用四驱轮式行走系统,前进和后退速度为0～5 km/h,可无级调速。传动系统采用机械式“H”型传动路线,通过纵梁内外双轴的设计将左右两侧的驱动力独立分开。采用离合器式转向分动器,通过转向分动箱内的牙嵌式离合器两两组合,完成底盘不同作业状态的控制,两路动力通过正转+正转、反转+反转、正转+反转和反转+正转4种状态的组合,实现拖拉机的前进、倒退、左右大小半径转向和原地转向。结果表明,整机最大牵引力为10.78 kN,最大及最小总传动比分别为732.50和73.25,前后驱动桥传动轴最高及最低转速分别为31.07和6.21 r/min。底盘的轮距和轴距比值为1,其所受滑移阻力矩与滚动阻力矩之和小于其所受驱动力矩,可在窄小地头实现原地转向,减小拖拉机田间作业的空行程,提高作业效率,有效保护农作物。 

Design of chassis transmission and steering system for Hilly Tractor

Aiming at the problems of poor adaptability of tractors in Hilly and mountainous areas, large turning radius in the field, easy to damage crops, long time-consuming and low efficiency, a 504-type hilly tractor chassis that can turn in situ is designed. The whole machine adopts a four-wheel drive walking system, with forward and backward speeds of 0-5km/h and stepless speed regulation. The transmission system adopts the mechanical "H" transmission route, and the driving forces on the left and right sides are separated independently through the design of the inner and outer double shafts of the longitudinal beam. The clutch type steering transfer gear is used to complete the control of different working states of the chassis through the combination of two tooth type clutches in the steering transfer box. The two-way power realizes the forward, reverse, left and right radius steering and in-situ steering of the tractor through the combination of four states: forward rotation + forward rotation, reverse rotation + reverse rotation, forward rotation + reverse rotation, reverse rotation + forward rotation. The results show that the maximum traction force of the whole machine is 10.78kN, the maximum and minimum total transmission ratios are 732.50 and 73.25, respectively. The maximum and minimum speeds of the front and rear drive axle drive shafts are 31.07r/min and 6.21r/min, respectively. The ratio of wheelbase to wheelbase of chassis is equal to 1, and the sum of sliding resistance moment and rolling resistance moment of chassis is less than the driving moment of chassis, which can realize in-situ steering in narrow ground, reduce the empty travel of tractor in field operation, improve operation efficiency and effectively protect crops.