履带式联合收获机差逆转向机构设计与试验

Design and Experiment of Differential Steering Mechanism for Track Combine Harvester

为减小履带式联合收获机在田间连续转向时对土壤产生的剪切破坏,增加整机在田间转向时的灵活性,提高作业效率,设计了一种差逆转向机构,可以实现差逆转向、切边转向和单边制动转向。在对差逆机构转向特性进行理论分析的基础上,应用Recur Dyn软件对其进行了不同工况下的动力学仿真,并将试制的差逆转向机构安装在履带式联合收获机上,在水泥地面及水稻田条件下进行转向性能试验。试验结果表明,在相同转向模式下,即近似相等的转向半径及转向角速度情况下,水稻田差逆转向半轴输出扭矩最大,达到5 668.2 N·m,远大于水泥地差逆转向的扭矩2 268.2 N·m,同时在3种转向模式中,差逆转向所要克服的阻力矩最大。在驱动轮输出转速75 r/min工况下,水泥地面中,差逆转向为0.610 rad/s;水稻田中,差逆转向为0.592 rad/s,较单边制动转向分别提高87.7%和88.5%;水稻田地差逆转向的最小转向半径的平均值为0.098 m,水泥地最小转向半径的平均值为0.082 m,转向占用面积显著减小;切边转向的角速度小且平稳,有助于对方向进行微调。该差逆转向机构使联合收获机的行走转向性能显著提高。

In order to solve the shearing damage caused by the track combine harvester continuous steering in the field,increasing the steering flexibility of vehicle,and improving operation efficiency,the driving performance simulation test of a pivot steering mechanism at the flat hard pavement and heavy clay was conducted. In the test,the multi-body dynamics model of the combine harvester was established in Recur Dyn software,and the movement state was obtained,including steering angular velocity,steering angular acceleration,steering radius and output torque. On this basis,the new type pivot steering mechanism and the walking performance test harvester were trial-produced,and a large number of experiments were carried out. Test results show that,under the same steering mode condition,the differential steering output torque in paddy field is maximum,up to 5 668. 2 N·m,much larger than that at the concrete floor,which is 2 268. 2 N·m,at the same time,the differential steering output torque is the biggest of the three steering modes. As the rotate speed of the driving wheel is 75 r / min,the angular velocity at the concrete floor is 0. 610 rad / s,and that of the paddy field is 0. 592 rad / s,which are improved by 87. 7% and 88. 5% separately; the minimum steering radius in the paddy field is 0. 098 m,and that of the concrete floor is 0. 082 m,which decrese the steering occupied area significately. The proposed differential steering mechanism improves the walking performance of the combine harvester greatly.