玉米高速免耕播种机液压主动仿形机构设计与试验

Design and Test of Hydraulic Active Profiling Mechanism for High-speed No-till Corn Planter

摘要:

为解决玉米免耕播种机在高速作业下播深一致性较差的问题，设计一种可调节液压仿形机构，并通过补偿调节的方式实现高精度的同步仿形。应用ANSYS软件对液压仿形机构进行静力学分析，求得液压缸初始伸出量与液压仿形机构最大应力应变之间的关系，分析结果表明，在伸出量30、40、50、60、70mm下，随着液压缸初始伸出量的增大，液压仿形机构最大应力显著降低、最大应变逐渐增加。为初步检验液压仿形机构作业性能，验证所设计滑动调节机构对其作业适应性的提升效果，使用播种单体仿形性能检测试验台，以液压缸初始伸出量和作业速度为试验因素，以上下仿形平均误差比、仿形平均误差、平均调节时长为试验指标，进行二因素五水平二次正交旋转组合试验。试验得出：当作业速度为12.3km/h时，滑动调节机构对调节精度的提升效果最佳，最大可使调节误差降低18.99%，当作业速度为14.8km/h时，滑动调节机构对调节速度的提升效果最佳，最大可使调节时长缩短16.11%，通过滑动调节机构可使得不同作业速度下仿形平均误差小于等于2.02mm、调节时长小于等于0.29s，满足设计要求。此外，为进一步验证液压仿形机构综合仿形性能，进行田间对比试验，结果表明：装备该液压仿形机构的播种单体播深合格率为94.8%，播深最大变异系数为6.12%，各项指标均满足玉米播种农艺要求。

Abstract:

In order to solve the problem of poor seeding depth consistency of no-till corn planter under high-speed operation environment, an adjustable hydraulic profiling mechanism was designed, which realized high-precision synchronous profiling by means of compensation adjustment. The application of ANSYS software on the hydraulic profiling mechanism for static analysis was carried out, to find the initial extensions of the hydraulic cylinder and hydraulic profiling mechanism of the maximum stress-strain value of the relationship between the analysis results showed that, in the 30mm, 40mm, 50mm, 60mm and 70mm extensions, with the increase of the initial amount of the hydraulic cylinder installation, the hydraulic profiling mechanism of the maximum stress value of a significant reduction in the maximum strain value was gradually increased. In order to preliminarily test the operational performance of the hydraulic profiling mechanism and verify the enhancement effect of the designed sliding adjustment mechanism on its operational adaptability, a two-factor, five-level quadratic orthogonal rotary combination test was conducted by using the pitching seeding unit profiling performance testing bench with the initial extensions of hydraulic cylinders and the operational speed as the test factors, and the ratio of the upper and lower profiling average error, the profiling average error, and the average adjustment time as the test indexes. When the operating speed was 12.3km/h, the sliding adjustment mechanism had the best effect on the improvement of adjustment accuracy, and it can reduce the adjustment error by 18.99%;when the operating speed was 14.8km/h, the sliding adjustment mechanism had the best effect on the improvement of adjustment speed, and it can shorten the adjustment time by 16.11%;and by sliding adjustment mechanism, the average error of the mimicry under different operating speeds was not more than 2.02mm, and the average error of the mimicry at different operating speeds was not more than 0.29s, which met the design requirements. In addition, in order to further verify the comprehensive profiling performance of the hydraulic profiling mechanism, the field comparison test was conducted, and the results showed that the qualified rate of seeding depth of the seeding unit equipped with the hydraulic profiling mechanism was 94.8%, and the maximum coefficient of variation of seeding depth was 6.12%, and all the indexes met the requirements of agronomy for corn seeding.